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Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Catherine A. Chamberlin, Ian P. Armstrong, Timothy J. Stagnitta, J. Baynes, A. Neale, T. Hultgren · U.S. Geological Survey

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Prepared in cooperation with the Rhode Island Water Resources Board

Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Scientific Investigations Report 2024–5109

U.S. Department of the Interior U.S. Geological Survey

Cover. Maps of Rhode Island, modified from figures in this report.

Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 By Catherine A. Chamberlin, Ian P. Armstrong, and Timothy J. Stagnitta

Prepared in cooperation with the Rhode Island Water Resources Board

Scientific Investigations Report 2024–5109

U.S. Department of the Interior U.S. Geological Survey

U.S. Geological Survey, Reston, Virginia: 2024

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Chamberlin, C.A., Armstrong, I.P., and Stagnitta, T.J., 2024, Estimating domestic self-supplied water use in Rhode Island, 2014–21: U.S. Geological Survey Scientific Investigations Report 2024–5109, 29 p., https://doi.org/10.3133/sir20245109. Associated data for this publication: Chamberlin, C.A., and Armstrong, I.P., 2024, Monthly and annual population and self-supplied domestic water withdrawal maps of Rhode Island, 2014–2021: U.S. Geological Survey data release, https://doi.org/ 10.5066/P9WU48KY ISSN 2328-0328 (online)

iii

Acknowledgments Kathleen Crawley and Patrick Killian of the Rhode Island Water Resources Board provided useful feedback to the direction of the project. Andrew Murray (U.S. Environmental Protection Agency) and Joshua Larsen (U.S. Geological Survey) provided peer reviews of this report. The authors appreciate the feedback of the following U. S. Geological Survey employees for technical review: Joe Ayotte, Luther Schalk, Paul Barlow, Rob Dudley, and Laura Medalie, who also assisted with project development.

Contents Acknowledgments��iii Abstract��1 Introduction��1 Purpose and Scope��2 Data and Methods��2 Population Rasters��2 Public Water System Boundaries��3 Per Capita Rates of Water Use��6 Water Volumes Withdrawn or Sold��6 Population Estimates��8 Water-Withdrawal Calculations��8 Results��10 Population Change Rasters��10 Population Served by Public Supply and Self-Supply Wells��10 Water Use and Water Withdrawal��10 Discussion��26 Conclusions��27 References Cited��28

Figures 1. 2. 3. 4. 5. 6. 7.

8. 9. 10. 11.

Map showing the study area��4 Map showing the U.S. Environmental Protection Agency 2010 dasymetric raster plotted for Rhode Island��5 Map of public water systems in Rhode Island in 2022��7 Map showing Voronoi polygons of daily per capita domestic water use rate coefficients in Rhode Island for January 2020��9 Map showing population change coefficients for block groups in Rhode Island between 2010 and 2020��11 Map showing seasonal scaling coefficients for block groups in Rhode Island in 2020��12 Graph showing recalculated population-served estimates of public water supply systems in Rhode Island for 2014–21 plotted against the reported population-served estimates��13 Graphs showing total populations in Rhode Island served by large public water systems, domestic self-supply wells, and small public water systems��13 Graph showing daily per capita domestic water use coefficients by month in Rhode Island for 2014–21��21 Map of domestic self-supply water withdrawals in Rhode Island for fiscal year 2020 for 12-digit hydrologic unit code subwatersheds��22 Graph showing time series of total domestic water withdrawals from self-supply wells in Rhode Island for 2014–21��26

Tables 1.

Populations who use domestic self-supply wells in Rhode Island by municipality for calendar years 2014–2021��14 2. Populations who use domestic self-supply wells in Rhode Island by 12-digit hydrologic unit code subwatershed for calendar years 2014–2021��17 3. Annual domestic self-supply water withdrawals by municipality in Rhode Island for fiscal years 2015–21��23 4. Annual domestic self-supply water withdrawals by 12-digit hydrologic unit code subwatershed in Rhode Island for fiscal years 2015–21��24

Conversion Factors U.S. customary units to International System of Units

Multiply

To obtain

Length foot (ft)

0.3048

meter (m)

yard (yd)

0.9144

meter (m)

Acre

0.004047

gallon (gal)

3.785

liter (L)

gallon (gal)

0.003785

cubic meter (m3)

Area square kilometer (km2)

Volume

million gallons (Mgal)

3,785

cubic meter (m3)

Flow rate gallon per day (gal/d)

0.003785

cubic meter per day (m3/d)

million gallons per day (Mgal/d)

0.04381

cubic meter per second (m3/s)

Datums Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

vii

Abbreviations ACS1

U.S. Census Bureau American Community Survey 1-year

ACS5

U.S. Census Bureau American Community Survey 5-year

gpcd

gallons per capita per day

HUC12

12-digit hydrologic unit code

PWS

public water system

RIWRB

Rhode Island Water Resources Board

SDWIS

Rhode Island Safe Drinking Water Information System

WUNDR

Rhode Island Water Use Needs, Data, and Reporting database

Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 By Catherine A. Chamberlin,1 Ian P. Armstrong,1 and Timothy J. Stagnitta2

Abstract Water withdrawal from private groundwater wells is often unaccounted for in water planning studies, and water from private wells can be a source of exposure to environmental contaminants. The sizes of populations that depend on private wells for domestic water use and the amounts of water that are withdrawn from these wells are generally poorly represented in data collection efforts because of the challenges of locating, metering, or gathering withdrawal information from individual property owners. To address this problem, the U.S. Geological Survey, in cooperation with the Rhode Island Water Resources Board, estimated the volume of water withdrawn from domestic self-supply wells and the populations who use them for the State of Rhode Island at a 30-meter pixel spatial resolution and one-month temporal resolution between July 2014 and June 2021. The number of people reliant on domestic self-supply wells has increased in Rhode Island over the study period; however, the statewide estimate of total water withdrawal has not statistically increased. Withdrawals from private wells are largest in the inland areas of the western part of the State, and the towns of Scituate and Charlestown have the highest estimated withdrawals. Statewide monthly withdrawals ranged from 3.987 million gallons per day in March 2018 to 7.767 million gallons per day in September 2016. The median per capita domestic water use rate was 46.0 gallons per capita per day.

Introduction Water for domestic use in the United States generally comes from either public water systems (PWSs) or private groundwater wells (domestic self-supply wells). Domestic water use includes water for indoor and outdoor household purposes, such as drinking, cleaning, cooking, bathing, and watering lawns and home gardens. Nationally, about 87 percent of the population is served by PWSs (Dieter 1U.S. Geological Survey. 2U.S. Geological Survey and the Rhode Island Water Resources Board.

and others, 2018). PWSs are generally more efficient than self-supply wells in terms of providing clean and treated water but require investment in physical infrastructure and have higher operation costs. In rural areas, investment requirements for public supply become much greater relative to the number of people served. Thus, the proportion of houses dependent on domestic self-supply wells tends to decrease as housing density increases (Johnson and others, 2019). The northeastern United States has the highest population density in the country, yet even in this region sizeable portions of the population rely on self-supply wells. Rhode Island has the second highest population density in the United States, and as much as 10 percent of the population is estimated to use self-supply wells (Johnson and others, 2022). Fifty-one percent of all estimated water withdrawals in Rhode Island in 2015 were for domestic use: 6.6 million gallons per day (Mgal/d) were from self-supply wells and 56 Mgal/d were deliveries from PWSs, out of total withdrawals of 122 Mgal/d (Dieter and others, 2018). An understanding of which populations use self-supply wells is important for managing water resources and assessing risk from various environmental contaminants. Domestic self-supply wells may be pathways through which populations are exposed to environmental and anthropogenic contaminants, such as arsenic, uranium, pesticides, fertilizers, and hydrocarbons (Bulka and others, 2022; DeSimone and others, 2014; Lombard and others, 2021; Soriano and others, 2022). Many well owners are unaware of the risk of possible exposure through self-supply wells because these wells are not frequently tested for contaminants that do not affect the taste or clarity of the water. Additionally, withdrawals from domestic self-supply wells (or any wells) may affect, or be affected by, changes in groundwater levels from drought or competing uses (Jasechko and Perrone, 2021; Mullaney, 2004). Though withdrawals from self-supply wells represent a relatively small percentage of total domestic water use in the United States (Dieter and others, 2018), in aggregate they may be a substantial part of overall water resources available in rural areas. Furthermore, because self-supply wells are commonly shallower than public-supply wells, they are more likely to be vulnerable to declines in water-table levels and contamination than public supply wells (DeSimone and others, 2014).

2 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 Despite their importance, determining the locations of domestic self-supply wells remains a challenge. Domestic self-supply wells are largely unregulated and are not subject to the reporting requirements placed on PWSs by State and Federal Government organizations (Bowen and others, 2019). Between 1960 and 1990, household water source was reported on the long-form decennial census questionnaire, but this questionnaire was only sent to a subset of the population (one in five households in 1990), and the question about household water source was removed after 1990. Many studies still use the results of the 1990 decennial census to estimate populations who use domestic self-supply wells (Wild and Nimiroski, 2007; Johnson and Belitz, 2017; Murray and others, 2021). A snapshot of county- and State-level estimates of total domestic water use (self-supplied water withdrawals and deliveries from PWSs) for 2015 is available in Dieter and others (2018); however, we are not aware of studies that estimate domestic self-supplied water withdrawals statewide at a greater spatial resolution than counties for any State other than Maine (Ryan P. Gordon, Amber H. Whittaker, and Robert G. Marvinney, Maine Geological Survey, written commun., 2021). The Rhode Island Water Resources Board (RIWRB) is an agency charged with managing the use and conservation of water throughout the State, including ensuring sufficient water supplies (Rhode Island General Assembly, 1956). As such, this agency has been working to amass comprehensive withdrawal information throughout Rhode Island, which is entered into the Water Use Needs, Data, and Reporting (WUNDR) database created by the RIWRB in collaboration with the University of Rhode Island and the Rhode Island Geological Survey (Rhode Island Water Resources Board, 2022). This database enables users to visualize and download water withdrawal and use information at the subwatershed scale, each of which is assigned a 12-digit hydrologic unit code (HUC12). Deliveries to domestic water users from large and small PWSs have been quantified through reporting (large PWSs report annually to the RIWRB) or through previous investigations (domestic use estimates for small PWSs were the subject of a previous study; Kathleen Crawley, RIWRB, written commun., 2022); however, withdrawals from domestic self-supply wells are not accounted for in these data. In order to provide comprehensive domestic water-use in Rhode Island, the U.S. Geological Survey, in cooperation with the RIWRB, generated data that provide estimates of the amounts of water withdrawn from domestic self-supply wells and the populations who use them (Chamberlin and Armstrong, 2024).

Purpose and Scope The purpose of this report is to (1) provide estimates of the population served by PWSs and domestic self-supply wells in Rhode Island and (2) provide estimates of the amount of domestic self-supplied water use in Rhode Island. Seasonal population estimates for winter (January 1 to

March 31 and October 1 to December 31) and summer (April 1 to September 30) and monthly domestic self-supplied water withdrawal estimates from July 2014 to June 2021 are provided as 30-meter (m) pixel raster datasets that can be aggregated to any level of interest for Rhode Island (Chamberlin and Armstrong, 2024). Results in this report are presented at scales of municipality and subwatershed (HUC12).

Data and Methods Estimates of populations served by public supply and domestic self-supply wells were generated by updating published population information for the State of Rhode Island and by using the spatial boundaries of PWS service areas to partition the population into areas that are served by public-supply or self-supply wells. Daily per capita domestic water use rates calculated from reported PWS water-use data were combined with the updated population estimates to generate estimates of water withdrawals from domestic self-supply wells.

Population Rasters Seasonal (summer and winter) statewide dasymetric population rasters were created by following methodology developed for Maine (Ryan P. Gordon, Amber H. Whittaker, and Robert G. Marvinney, Maine Geological Survey, written commun., 2021). Dasymetric maps reorganize map data from a collection unit (such as a census block group) into more precise areas using additional information (such as land cover; Baynes and others, 2022). Briefly stated, this method was applied to update populations from a 2010 national dasymetric raster (U.S. Environmental Protection Agency, 2016) for each season from 2014 to 2021 on the basis of U.S. Census Bureau American Community Survey 5-year (ACS5) estimates. All U.S. Census Bureau data for this project were acquired through the National Historic Geographic Information System supported by IPUMS (Manson and others, 2023). The base 2010 national dasymetric raster was clipped to the State of Rhode Island (figs. 1 and 2). The base 2010 national dasymetric raster (U.S. Environmental Protection Agency, 2016) was generated by using the 2011 National Land Cover Database release (Homer and others, 2015) and the 2010 U.S. Census Bureau decennial census (Manson and others, 2023). The product attributed the populations reported in the 2010 decennial census for each census block group to 30-m pixels of developed land from the National Land Cover Database, as well as some additional processing that is detailed in U.S. Environmental Protection Agency (2016). Population changes were calculated for each year at the census block group level as the percent change in population between the 2010 decennial census count (on which the U.S. Environmental Protection Agency dasymetric raster

Data and Methods 3 was based) and the ACS5 population estimates for 2014–19 and 2021. For 2020, the estimates were taken from the 2020 decennial census count. The block group boundaries were static between 2010 and 2019, and no adjustments were made for these years. Block group boundaries were redrawn, however, for the 2020 census: some block groups were merged or split, and the boundaries of others were altered. Because the base population map was generated from the 2010 census boundaries, we remapped the 2020 and 2021 census populations to 2010 census boundaries. Using the published nationwide relationship files for 2020 and 2010 block groups (U.S. Census Bureau, 2023), we divided the 2020 boundary population values into each area of overlapping land area by assuming population was evenly distributed across land area and then recombined values on the basis of the 2010 block group associations. Block groups in Rhode Island had a median land area of 0.88 square kilometer in 2010 and 0.94 square kilometer in 2020. Block group population estimates from the ACS5 are published yearly, but they represent the average of the 5 years leading up to the publication year. A similar product, the U.S. Census Bureau American Communities Survey 1-year (ACS1; Manson and others, 2023) was used to adjust for the 5-year averaging. The ACS1 population estimates represent the value for the reported year only; however, these estimates have a great amount of error at small spatial scales, making them unsuitable for use at subcounty scales. The ACS1 population estimates of larger areas, such as States, are more robust. To adjust the block group population estimates for the 5-year averaging in the ACS5 data, the statewide sum of each yearly dasymetric raster was compared with the published ACS1 population of Rhode Island. Then, each pixel was multiplied by a coefficient C for each year y, described as

Py  C y = _ , n ∑ i=1 di,  y

(1)

where P

represents the published ACS1 population for Rhode Island in year y,

represents the population of the dasymetric raster for pixel i and year y, and

is the number of pixels in the dasymetric raster of Rhode Island.

This equation adjusts the total statewide population of the dasymetric rasters to be equal to the published ACS1 statewide population, while preserving the spatial distributions of populations described by the ACS5 data. Many parts of Rhode Island, such as the coastlines of southern Rhode Island, are popular summer tourist destinations, which affects the seasonal population of these areas. For each block group, we based the amount of the seasonal population variation on ASC5 estimates (and

decennial census count values for 2020) of the fraction of housing units that are classified as “vacant for seasonal recreational use.” Using the yearly dasymetric rasters as the baseline population, we assumed that the size of households vacant for seasonal recreational use were the same as the year-round households and calculated the summer population estimates for each pixel as

HV  P S = P W(1 + _), HO 

(2)

where P S

is the summer population of a pixel,

P W

is the winter population of a pixel,

H V

is the number of seasonally vacant housing units in the census block group intersecting with a pixel and

H O

is the number of occupied housing units.

After discussion with experts at the RIWRB with knowledge of seasonal tourism in Rhode Island, seasonal adjustments were applied to create summer population estimates, and year-round population estimates from the U.S. Census Bureau were used for winter population estimates (Kathleen Crawley, RIWRB, oral commun., 2022).

Public Water System Boundaries Domestic self-supply wells were assumed to be the source of water in areas of the State outside the boundaries of PWS service areas. For this analysis, boundaries for all PWS service areas in Rhode Island were used, including community (serving primarily domestic water users) and noncommunity (which may provide water for other uses as well, such as schools or businesses) boundaries. All areas within Rhode Island that were outside of PWS boundaries were assumed to be served by domestic self-supply wells. To obtain geospatial boundaries of the service areas of PWSs, we used different methods for large (defined as >50 million gallons per year) and small (defined as <50 million gallons per year and >10 connections) systems. The boundaries of 28 large PWS service areas were obtained from the Rhode Island Geographic Information System (2022). Adjustments were made to account for the mergers of two PWSs (East Smithfield Water District and Johnston Water Control Facilities) with a larger PWS (Providence Water) during the study period (East Smithfield in 2017 and Johnston in 2020). A PWS boundary shapefile that represented 1995 system boundaries (Kathleen Crawley, RIWRB, written commun., 2020) provided historical boundaries that were used to separate the district of Johnston Water Control Facilities from Providence Water for 2014–19, and the East Smithfield Water District from Providence Water for 2014–16.

4 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 −71°50'

−71°40'

−71°30'

Br a

42°

iver hR nc

Burrillville

−71°20'

−71°10'

−70°50'

−71°

Woonsocket ME

North Smithfield

Attleboro

VT Taunton

Glocester

MA Map area Providence

41°50'

Scituate

ux et

Woonasquatucket River

er Riv

Somerset

t aw

Fall River

West Warwick

Bristol

41°40'

New Bedford o Wo

Narragansett Bay

Bliss Corner

r ive

Newport

41°30'

Little Compton

Kingston

er South Kingstown

k Riv

atuc

c Paw

Narragansett Pier

Charlestown

Westerly 41°20'

EXPLANATION Rhode Island state boundary Town

Block Island Sound

0 41°10'

15 MILES

New Shoreham Block Island

15 KILOMETERS

Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 1. Map showing the study area, which encompasses the State of Rhode Island. The study area excludes adjacent water bodies within the State borders, such as Narragansett Bay and Block Island Sound.

Data and Methods 5 −71°50'

−71°40'

−71°30'

42°

−71°20'

−71°10'

−70°50'

−71°

Woonsocket Attleboro Taunton

Providence

41°50'

Somerset

West Warwick

Fall River Bristol

41°40'

New Bedford Narragansett Bay

Bliss Corner

Newport

41°30'

Kingston

Narragansett Pier

Westerly

EXPLANATION

41°20'

Population per 30-meter pixel in 2010 0.01 to 0.50

5.01 to 50.00

0.51 to 5.00

50.01 to 608.73

Rhode Island State boundary Town 0 41°10'

15 MILES

New Shoreham Block Island

15 KILOMETERS

Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 2. Map showing the U.S. Environmental Protection Agency 2010 dasymetric raster plotted for Rhode Island. Data from U.S. Environmental Protection Agency (2016).

6 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 The boundaries of the small community and noncommunity PWS service areas were generated manually for this project. A list of 416 small providers in the Rhode Island Safe Drinking Water Information System (SDWIS; maintained by the Rhode Island Department of Health and accessible through the Rhode Island Drinking Water Viewer; Rhode Island Department of Health, 2024) was obtained in 2020. Metadata in SDWIS was first used to identify the general service area of a PWS; then, more precise boundaries of service areas were estimated on a building-by-building basis. Geospatial boundaries were manually drawn around clusters of buildings assumed to be within the service area for each small provider. Service areas of large PWSs make up 50 percent of the area of Rhode Island. Service areas of the small PWSs are estimated to be 1 percent of the area of the State. The large PWSs are concentrated around the Narragansett Bay, where population density is highest (figs. 2 and 3). Small PWSs are primarily scattered throughout the western half of the State, though they can also be found on islands in the Narragansett Bay, within pockets surrounded by large PWSs, and in other parts of the State (fig. 3).

Per Capita Rates of Water Use Daily per capita domestic water use was calculated from available water-use data of selected PWSs throughout the State. Nineteen systems were selected on the basis of the completeness and availability of monthly residential water sales or withdrawal data for both seasons. Additional criteria for selection of representative PWSs were that (1) they were in operation in 2010 and would therefore be represented by the base 2010 dasymetric raster (U.S. Environmental Protection Agency, 2016), (2) the seasonality of reported water use matched expected patterns for domestic water use (higher in summer than winter), and (3) the calculated daily per capita residential water use coefficients did not greatly exceed those reported for domestic use in Dieter and others (2018), here defined as being >200 gallons per capita per day (gpcd). Water retail sales data for 10 large PWSs were obtained from annual reports submitted to the RIWRB. These systems serve a variety of customer types, but only the sales to residential customers (including both single and multi-family customers) were used because these were assumed to represent domestic water use. Metered water withdrawal data for the small systems were provided by an engineering firm overseeing many water systems to RIWRB, and the 9 small systems used in this study represent systems serving exclusively residential communities. Therefore, water withdrawal was assumed to represent domestic water use in these systems. The 19 selected systems are highlighted in figure 3.

To calculate per capita rates of domestic water use, data on volumes of withdrawals (for the 9 small systems) or water sales (for the 10 large systems) were converted to per capita rates by using computed estimates of the population served for each system (described in the report section “Population Served by Public Supply and Self-Supply Wells”). These per capita water use rates were applied to areas of domestic self-supply on the basis of physical nearness by using the simplifying assumption that water-use behavior might vary across parts of the State but does not vary between domestic water users regardless of whether the source of water is a public-supply or self-supply well.

Water Volumes Withdrawn or Sold The RIWRB collects annual reports from all large PWSs each year, which includes monthly residential water-use sales by volume (Kathleen Crawley, RIWRB, written commun., 2020). Monthly residential data were compiled for 10 large PWSs from July 2014 to June 2021. Initial quality assurance and quality control included checking that sales data remained within the same order of magnitude across a time series; values outside of these criteria were investigated for errors in reporting units. Monthly values that appeared to be outliers or that were missing were flagged, and the RIWRB contacted the individual PWS to resolve flagged data. No efforts were made to fill gaps in a time series if the RIWRB was unable to obtain records or corrections from the suppliers. The monthly data for each system were then converted to mean daily water use volumes according to the number of days in each month. Small PWSs are not required to submit annual reports to the RIWRB. However, an engineering firm that operates dozens of small PWSs in the State provided metered information for nine small community (residential) suppliers (Kathleen Crawley, RIWRB, written commun. 2022). For these systems, volume per day was calculated as the change in total metered volume divided by the number of days between meter readings. We excluded periods between meter reads that were greater than 6 months because this exceeded the seasonal resolution of our population estimates. In several instances, the engineering firm that provided these data had adjusted the volume per day measurements on the basis of knowledge of their operations (for example, meter replacements or recalibrations); these changes were incorporated into our study. If a single system withdrew water from multiple wells, the volume per day withdrawals from the wells were summed to get a systemwide total. The daily withdrawals were averaged over each month.

Data and Methods 7 −71°50'

−71°40'

−71°30'

42°

−71°20'

−71°10'

−70°50'

−71°

EXPLANATION

Woonsocket

Large supplier Attleboro

Large supplier—Used to calculate daily per capita coefficients Small supplier Taunton

Small supplier—Used to calculate daily per capita coefficients Rhode Island State Boundary Town

Providence

41°50'

Somerset

Fall River

West Warwick

Bristol

41°40'

New Bedford Narragansett Bay

Bliss Corner

Newport

41°30'

Kingston

Narragansett Pier

Westerly 41°20'

New Shoreham 41°10'

Block Island

0 0

5 5

10 10

15 MILES

15 KILOMETERS

Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 3. Map of public water systems in Rhode Island in 2022. Service area boundaries from Rhode Island Geographic Information System (2022) and this study.

8 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Population Estimates For the 10 large PWSs, reported populations served were obtained from the annual reports submitted to the RIWRB. Annual reports are generally reported for fiscal years (defined as the 12-month period from July 1 to June 30 and designated by the calendar year in which it ends), and we therefore used the end of one fiscal year and the beginning of the next as the time step for year-to-year population changes when comparing these annual report values with recalculated population-served values described in the report section “Population Served by Public-Supply and Self-Supply Wells.” The methods used to estimate populations served that are reported to the RIWRB varied widely among suppliers, from values based on the number of service connections to values based on professional estimates of tourist activity (Kathleen Crawley, RIWRB, written commun. 2023). For small PWSs, reported populations served were obtained from metadata in the SDWIS and from a report that summarized small PWS populations served in Rhode Island (Kathleen Crawley, RIWRB, written commun. 2022). SDWIS population-served estimates are generated by the Rhode Island Department of Health using methodology that differs from methods used for the large PWSs. Owing to the variation in methodology of estimates of reported populations served, for consistency, we recalculated populations served for all large and small PWSs using the boundary polygons for each PWS and the population dasymetric rasters created for each season in this study. The per capita rates of water use were calculated by using our recalculated population-served values.

For all PWSs, recalculated populations served were derived from summer and winter dasymetric rasters for each year, and from the spatial polygons of system service-area boundaries. Populations served were calculated by summing raster pixel values within the polygons using the terra package in R (Hijmans, 2023). Small PWSs are required to register with SDWIS if they serve an average of at least 25 people for at least 60 days per year or have at least 15 service connections. Therefore, we adjusted any recalculated populations served of fewer than 25 people to 25 people.

Water-Withdrawal Calculations Water withdrawal in gallons per day was calculated for each pixel as the product of population per pixel and the per capita water-use rate in gallons per person per day. Per capita water-use rates from the supplier data were applied across the State using nearest neighbor assignments. Differences in per capita water-use rates between suppliers were considered to be representative of regional water use, incorporating variations in water use on the basis of variations in weather patterns, land use, and socioeconomics across the State. For each month, the State was divided into Voronoi polygons surrounding suppliers who had reported data for the given month. Voronoi polygons depict areas of the State that are spatially closest to each of these suppliers (fig. 4). The Voronoi polygons were converted to rasters at the same resolution as the seasonal dasymetric rasters. For each fiscal year, the total withdrawal for each pixel (in Mgal/d) was calculated as a weighted average of the monthly rasters (also in Mgal/d), weighted by the number of days in each month.

Data and Methods 9 −71°50'

−71°40'

−71°30'

42°

−71°20'

−71°10'

−70°50'

−71°

EXPLANATION

Woonsocket

Domestic water use in January 2020, in gallons per capita per day 18.53 to 30.50

Attleboro

30.51 to 42.50 Taunton

42.51 to 54.50 54.51 to 66.50 66.51 to 78.50 41°50'

Public water system area boundary Voronoi polygon boundary Rhode Island State boundary Town

Providence

Somerset

Fall River

West Warwick

Bristol

41°40'

New Bedford Narragansett Bay

41°30'

Bliss Corner

Newport

Kingston

Narragansett Pier

Westerly 41°20'

0 41°10'

15 MILES

New Shoreham 0

15 KILOMETERS

Block Island Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 4. Map showing Voronoi polygons of daily per capita domestic water use rate coefficients in Rhode Island for January 2020. Public water system service boundaries that the daily per capita domestic water use rates were calculated from are overlain for reference. Data from Rhode Island Geographic Information System (2022).

10 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Results All spatial results of this study are generated as 30-m monthly rasters (Chamberlin and Armstrong, 2024) that can be used as input for further applications by any interested parties. This report summarizes results by municipality and subwatershed (HUC12).

Population Change Rasters Population in Rhode Island has generally been increasing since 2010; however, increases are not consistent across the State. In 2020, 98.7 percent of block groups had population change coefficients between −1 and 1 (unitless), with a median change of 0.04 (fig. 5). Block groups along the coastline, on Block Island, and along Narragansett Bay generally had the highest seasonality coefficients, sometimes exceeding 2 (a doubling of population in the summer), indicating the highest variability between summer and winter populations (fig. 6). Statewide in 2020, 79 percent of block groups had seasonality coefficients of 1 (meaning there were no vacant seasonal units in the block group), and 98.9 percent of block groups had seasonality coefficients less than 2.

Population Served by Public Supply and Self-Supply Wells Our recalculated estimates of population served by each PWS generally agreed with reported values (Kendall’s τ = 0.78; fig. 7). This association was stronger for the larger suppliers (Kendall’s τ = 0.89) than for the smaller suppliers (Kendall’s τ = 0.39). For large PWSs, the median difference between values was 6.6 percent of the reported population values, whereas for small suppliers the median difference was 27 percent of the reported value. This difference was largely driven by smaller reported populations for the small districts (median reported population of 170 people; Kathleen Crawley, RIWRB, written commun., 2020) than for the large districts (median reported population of 40,000 people; Kathleen Crawley, RIWRB, written commun., 2020; Rhode Island Department of Health, 2024). There was little bias overall (percent bias = 0.8 percent); however, the recalculated population-served estimates for the small PWSs were biased low compared with the reported population-served estimates (percent bias = −46.8 percent). We found that the recalculated population served by a PWS increased over time for large PWSs (seasonal Mann-Kendall, p < 0.001, Sen slope = 1,591 people per month; fig. 8) but did not change significantly over time for small PWSs (seasonal Mann-Kendall, p = 0.46). Much of the change for large PWSs occurred between 2019 and 2020. Population served by large PWSs was lowest in October–December 2014 (934,295 people), and highest in April–September 2020 (1,004,405 people). Over

the timeframe of this study, a median of 20,440 people were served by small PWSs in winter, and a median of 21,961 people were served in summer (fig. 8). Estimates of the statewide population served by domestic self-supply wells increased over fiscal years 2015–21 (seasonal Mann-Kendall, p = 0.01, Sen slope = 253 people per month; fig. 8). Much of this increase occurred between 2019 and 2020, and Rhode Island reported an increase in population that year of 3.5 percent (Manson and others, 2023). Though 2020 data came from the decennial census and 2019 data came from the American Community Survey, the increase continued in 2021, which also used data from the American Community Survey. This increase was exaggerated in some locations, such as in the two block groups on Block Island, which together had a 54 percent increase in reported population from 2019 to 2020 (916 people to 1,410 people); however, reported population decreased in 2021 to 1,007 people. As Block Island has a large number of seasonally vacant units (1,444 units out of 1,947 total units in 2020; Manson and others, 2023), this population increase was even greater in the summer using our methodology. Populations who relied on self-supply wells varied spatially: the largest populations of self-supply well users were in the towns of Charlestown, Glocester, Scituate, Burrillville, and North Smithfield (table 1) and in the drainage basins of Branch River, Woonasquatucket River, Moswansicut Pond-Huntinghouse Brook, Upper Wood River, and Tomaquag Brook-Pawcatuck River3 (table 2; Moswansicut Pond, Huntinghouse Brook, and Tomaquag Brook not shown on any map). The largest differences between summer and winter populations who use domestic self-supply wells were seen in the towns of Charlestown, Glocester, Little Compton, New Shoreham, and South Kingstown. Populations who use domestic self-supply wells are available in Chamberlin and Armstrong (2024) and can be aggregated to other spatial resolutions as well.

Water Use and Water Withdrawal The median daily per capita domestic water use rate calculated in this study from the 19 PWSs was 46.0 gpcd, and the 95-percent confidence interval was 20.1–108.2 gpcd (fig. 9). Overall, seasonality was significant (Kruskal-Wallis test on months, p < 0.05): the highest daily per capita domestic water use rates were in August–October (medians of 56.3, 55.5, and 54.4 gpcd, respectively), and the lowest daily per capita domestic water use rates were in March–May (medians of 39.1, 39.3, and 38.5 gpcd, respectively). No significant annual trend was seen over the period of this study in the daily per capita domestic water use rates (seasonal Mann-Kendall test, 11 degrees of freedom, p = 0.29).

3HUC12s 010900030204, 010900040502, 010900040604, 010900050101, and 010900050205.

Results 11 −71°50' 42°

−71°40'

−71°30'

−71°20'

−71°10'

EXPLANATION

Woonsocket

Population change coefficient for 2020—percent change relative to 2010 −0.920 to −0.100 Taunton −0.099 to 0.100 0.101 to 1.000 1.001 to 5.000 5.001 to 16.450 Block group boundary Rhode Island State boundary Town

Attleboro

41°50'

−70°50'

−71°

Providence

Somerset

West Warwick

Fall River Bristol

41°40'

New Bedford Narragansett Bay

Bliss Corner

Newport

41°30'

Kingston

Narragansett Pier

Westerly 41°20'

0 41°10'

15 MILES

New Shoreham 0

15 KILOMETERS

Block Island Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 5. Map showing population change coefficients for block groups in Rhode Island between 2010 and 2020. Data from Chamberlin and Armstrong (2024).

12 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 −71°50'

−71°40'

−71°30'

42°

−71°20'

−71°10'

−70°50'

−71°

EXPLANATION

Woonsocket

Seasonal coefficients for 2020—ratio of summer to winter populations 1

Attleboro

1.01 to 2.00

Taunton

2.01 to 10.00

10.01 to 98.00 Block group boundary Rhode Island State boundary Town

41°50'

Providence

Somerset

West Warwick

Fall River Bristol

41°40'

New Bedford Narragansett Bay

Bliss Corner

Newport

41°30'

Kingston

Narragansett Pier

Westerly 41°20'

0 41°10'

15 MILES

New Shoreham 0

15 KILOMETERS

Block Island Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 6. Map showing seasonal scaling coefficients for block groups in Rhode Island in 2020. Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30. Data from Chamberlin and Armstrong (2024).

Results 13 1,000,000

Large public water systems

Domestic self-supply wells

Small public water systems

1,050,000

1,000,000 :1 eq uiv ale nc y

10,000

1,000

950,000

Lin eo f1

Population recalculated

100,000

900,000

100

140,000 10

100

1,000

10,000

100,000

1,000,000

Population reported EXPLANATION Population served by a public water system during one month between July 2014 and June 2022

Figure 7. Graph showing recalculated population-served estimates of public water supply systems in Rhode Island for 2014–21 (y-axis) plotted against the reported population-served estimates (x-axis).

The greatest amount of domestic self-supply water withdrawal occurred in the western part of the State, which is the area with the largest number of people who rely on self-supply wells (fig. 10). Total self-supplied domestic withdrawals varied by municipality and drainage basin, and the greatest total annual withdrawals were in the towns of Scituate (an average of 0.459 Mgal/d between July 2014 and June 2021) and Charlestown (an average of 0.438 Mgal/d between July 2014 and June 2021), and in the drainage basins of the Tomaquag Brook-Pawcatuck River4 (an average of 0.379 Mgal/d between 2014 and 2021) and Woonasquatucket River5 (an average of 0.342 Mgal/d between 2014 and 2021; tables 3 and 4). Statewide, total monthly withdrawals from private wells ranged from 3.987 Mgal/d in March 2018 to 7.767 Mgal/d in September 2016, and no trend over time was detected in the monthly values (seasonal Mann-Kendall test on months, 11 degrees of freedom, p = 0.24; fig. 11). Statewide, water withdrawals from self-supply wells are generally higher in summer than in winter, similar to the seasonal pattern of use for PWSs (Stagnitta and Medalie, 2023).

4HUC12 010900050205. 5HUC12 010900040502.

Total population served

130,000 120,000 110,000 100,000

26,000 24,000 22,000 20,000 18,000

2014

2015

2016

2017

2018

2019

2020

2021

Year EXPLANATION Population served by a public water system or domestic self-supply well during one month between July 2014 and June 2022

Figure 8. Graphs showing total populations in Rhode Island served by A, large public water systems reporting to the Rhode Island Water Resources Board (RIWRB); B, domestic self-supply wells; and C, small public water systems not reporting to the RIWRB. Data from Chamberlin and Armstrong (2024).

[Data from Chamberlin and Armstrong (2024). Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30.]

Municipality Barrington Bristol Burrillville Central Falls Charlestown Coventry Cranston Cumberland East Greenwich East Providence Exeter Foster Glocester Hopkinton Jamestown

Season

Population per calendar year 2014

2015

2016

2017

2018

2019

2020

2021

Summer

Winter

Summer

1,784

1,919

2,004

2,087

2,148

2,190

1,602

1,986

Winter

1,765

1,902

1,987

2,077

2,147

2,182

1,593

1,974

Summer

8,522

8,244

8,088

8,254

8,291

8,750

8,470

8,478

Winter

8,379

8,107

7,883

8,038

8,035

8,227

8,087

8,059

Summer

Winter

Summer

9,606

10,036

10,017

9,954

10,238

10,139

10,227

10,152

Winter

7,053

7,028

6,999

7,022

7,024

7,012

7,210

7,214

Summer

7,640

7,641

7,323

7,158

7,208

7,370

7,559

7,880

Winter

7,453

7,435

7,096

6,990

6,928

7,123

7,326

7,717

Summer

1,616

1,633

1,626

1,604

1,481

1,458

1,731

1,683

Winter

1,599

1,633

1,620

1,598

1,476

1,453

1,726

1,683

Summer

1,138

1,121

1,156

1,086

1,051

931

1,235

912

Winter

1,136

1,085

1,113

1,044

1,016

909

1,235

912

Summer

947

889

952

937

1,001

929

944

Winter

926

870

936

917

982

929

884

883

Summer

Winter

Summer

6,154

6,104

6,136

6,292

6,353

6,173

6,031

6,331

Winter

6,118

6,104

6,136

6,166

6,202

6,043

5,864

6,243

Summer

4,554

4,578

4,574

4,605

4,587

4,595

4,352

4,403

Winter

4,532

4,558

4,556

4,585

4,565

4,595

4,352

4,403

Summer

9,049

9,348

9,486

9,498

9,693

9,863

9,813

9,996

Winter

8,880

9,017

9,055

9,093

9,291

9,399

9,142

9,253

Summer

7,797

7,852

7,928

7,730

7,868

7,978

8,216

8,207

Winter

7,495

7,509

7,510

7,520

7,505

7,530

7,738

7,782

Summer

3,476

3,343

3,352

3,191

3,251

2,997

3,379

3,797

Winter

2,742

2,702

2,902

2,771

2,979

2,880

2,898

3,093

14 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Table 1. Populations who use domestic self-supply wells in Rhode Island by municipality for calendar years 2014–2021.

Table 1. Populations who use domestic self-supply wells in Rhode Island by municipality for calendar years 2014–2021.—Continued [Data from Chamberlin and Armstrong (2024). Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30.]

Municipality Johnston Lincoln Little Compton Middletown Narragansett New Shoreham Newport North Kingstown North Providence North Smithfield Pawtucket Portsmouth Providence Richmond

Population per calendar year 2014

2015

2016

2017

2018

2019

2020

2021

Summer

1,463

1,744

1,579

1,496

1,486

1,467

1,536

1,666

Winter

1,463

1,744

1,579

1,496

1,486

1,467

1,536

1,666

Summer

Winter

Summer

4,747

4,790

4,713

4,814

4,794

4,916

5,057

5,079

Winter

3,439

3,455

3,443

3,473

3,448

3,435

3,554

3,536

Summer

2,183

2,020

1,859

1,814

1,695

1,614

1,882

1,594

Winter

2,053

1,840

1,730

1,592

1,429

1,327

1,466

1,285

Summer

Winter

Summer

2,329

2,302

2,168

2,187

2,216

2,305

7,016

2,454

Winter

531

536

525

494

483

535

851

601

Summer

132

120

138

169

136

158

255

202

Winter

136

110

Summer

1,163

1,143

1,175

1,174

1,185

1,303

1,360

Winter

1,108

1,117

1,098

1,132

1,134

1,136

1,247

1,293

Summer

Winter

Summer

7,822

7,882

7,739

7,871

7,836

7,868

8,051

8,376

Winter

7,739

7,864

7,718

7,804

7,764

7,820

7,988

8,305

Summer

Winter

Summer

567

494

517

520

517

700

682

Winter

490

420

455

465

463

453

629

620

Summer

Winter

Summer

6,706

6,659

6,618

6,647

6,686

6,710

6,950

7,122

Winter

6,502

6,504

6,516

6,539

6,554

6,603

6,832

6,946

Summer

9,065

9,110

9,080

9,245

9,170

8,953

9,021

Winter

9,043

9,089

9,080

9,165

9,085

9,065

8,888

8,921

Results 15

Scituate

Season

[Data from Chamberlin and Armstrong (2024). Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30.]

Municipality Smithfield South Kingstown Tiverton Warren Warwick West Greenwich West Warwick Westerly Woonsocket Rhode Island

Season

Population per calendar year 2014

2015

2016

2017

2018

2019

2020

2021

Summer

3,188

3,136

3,159

3,184

3,185

3,166

3,454

3,546

Winter

3,185

3,133

3,159

3,184

3,185

3,165

3,454

3,546

Summer

3,081

3,152

3,330

3,376

3,636

3,645

4,132

4,000

Winter

2,663

2,725

2,896

2,881

3,083

3,084

3,356

3,203

Summer

5,520

5,569

5,463

5,399

5,340

5,288

5,957

5,381

Winter

5,136

5,119

5,078

4,998

4,933

4,896

5,232

4,806

Summer

500

457

443

463

460

466

494

508

Winter

459

425

415

429

436

480

477

Summer

859

767

932

900

640

709

844

1,074

Winter

857

764

929

897

638

707

843

1,073

Summer

4,629

4,490

4,508

4,479

4,295

4,205

4,326

4,253

Winter

4,628

4,489

4,506

4,477

4,291

4,204

4,326

4,253

Summer

Winter

Summer

470

507

533

564

530

507

511

623

Winter

435

459

490

511

477

447

455

555

Summer

Winter

Summer

117,044

117,409

116,925

117,057

117,337

117,625

125,323

122,059

Winter

108,192

107,985

107,781

107,729

107,419

107,435

109,658

110,745

16 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Table 1. Populations who use domestic self-supply wells in Rhode Island by municipality for calendar years 2014–2021.—Continued

Table 2. Populations who use domestic self-supply wells in Rhode Island by 12-digit hydrologic unit code (HUC12) subwatershed for calendar years 2014–2021. [Data from Chamberlin and Armstrong (2024). HUC12s from U.S. Geological Survey (2020), accessed with nhdplusTools (Blodgett and Johnson, 2023). Map labels correspond to labels on figure 10. Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30. —, no data]

Map label

Subwatershed name

HUC12

Percent of subwatershed in Rhode Island

Population per calendar year Season

2014

2015

2016

2017

2018

2019

2020

2021

Cape Cod Bay drainage basin 1 2

Westport River

010900020502

Cold Brook-Rhode Island Sound

010900020503

Clear River

010900030202

12 77

Winter

1,989

1,930

1,870

1,735

1,770 2,028

1,791

Summer

2,095

2,046

2,041

1,991

1,803

1,843 2,215

1,944

Winter

2,352

2,344

2,350

2,376

2,341

2,373 2,433

2,561

Summer

3,404

3,402

3,370

3,442

3,401

3,538 3,396

3,589

Blackstone River drainage basin 3 4 5 6

Chepachet River Branch River Mill River

010900030203 010900030204 010900030205

75 100 98 2

Emerson BrookBlackstone River

010900030206

Abbott Run

010900030207

Peters River-Blackstone River

010900030208

Winter

4,602

4,468

4,303

4,508

4,335

4,306 4,098

4,741

Summer

4,708

4,595

4,485

4,700

4,569

4,736 4,421

5,098

Winter

4,355

4,223

4,402

4,360

4,260

4,353 4,361

3,923

Summer

4,388

4,265

4,466

4,429

4,321

4,398 4,384

3,923

Winter

7,190

7,108

6,944

6,776

6,934

7,161 7,469

7,253

Summer

7,261

7,112

6,972

6,835

6,991

7,250 7,548

7,337

Winter

0 0

Summer

0 0

Winter

2,153

2,357

2,330

2,415

2,377

2,489 2,380

2,291

Summer

2,168

2,365

2,340

2,426

2,388

2,490 2,383

2,296

Winter

680

650

646

614

616

573 706

585

Summer

682

666

665

633

632

582 706

585

Winter

1,249

1,225

1,230

1,195

1,176

1,133 1,403

1,267

Summer

1,255

1,250

1,260

1,227

1,207

1,150 1,413

1,279

Narragansett Bay drainage basin Ten Mile River

010900040401

Moshassuck River

010900040501

100

Woonasquatucket River

010900040502

100

Big River

010900040601

100

Winter

0 0

Summer

0 0

Winter

110

117

124

115

131

147 168

222

Summer

110

117

124

115

131

147 168

222

Winter

6,377

6,529

6,336

6,387

6,292

6,273 6,612

6,942

Summer

6,414

6,637

6,445

6,482

6,429

6,398 6,882

7,272

Winter

2,267

2,243

2,148

2,280

2,105

2,101 2,316

2,230

Summer

2,282

2,269

2,168

2,301

2,133

2,125 2,328

2,238

Results 17

[Data from Chamberlin and Armstrong (2024). HUC12s from U.S. Geological Survey (2020), accessed with nhdplusTools (Blodgett and Johnson, 2023). Map labels correspond to labels on figure 10. Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30. —, no data]

Map label

Subwatershed name

HUC12

Percent of subwatershed in Rhode Island

Population per calendar year Season

2014

2015

2016

2017

2018

2019

2020

2021

Narragansett Bay drainage basin—Continued 14 15

Flat River Reservoir

010900040602

100

South Branch Pawtuxet River

010900040603

Moswansicut PondHuntinghouse Brook

010900040604

Barden ReservoirPonaganset River

010900040605

Scituate Reservoir

010900040606

100

North Branch Pawtuxet River

010900040607

100

Pocasset River

010900040608

100

Pawtuxet River

010900040609

100

16 17

22 23 24 25

Palmer River

010900040701

Barrington River-Warren River

010900040702

Quequechan River

010900040803

100 100 100

6 51 2

Seekonk River-Providence River

010900040901

Old Mill CreekNarragansett Bay

010900040902

Greenwich Bay

010900040903

Winter

5,399

5,441

5,248

5,222

5,257

5,397 5,542

5,722

Summer

5,571

5,614

5,452

5,371

5,502

5,613 5,745

5,853

Winter

4 4

Summer

4 4

Winter

5,622

5,697

5,411

5,629

5,518

5,102 5,055

5,052

Summer

5,655

5,789

5,502

5,778

5,707

5,286 5,317

5,393

Winter

3,714

3,789

3,735

3,509

3,887

3,756 3,492

3,585

Summer

3,753

3,830

3,802

3,584

3,935

3,841 3,567

3,656

Winter

4,146

4,354

4,391

4,439

4,394

4,626 4,399

4,454

Summer

4,162

4,370

4,391

4,439

4,394

4,626 4,399

4,454

Winter

1,756

1,688

1,753

1,728

1,841

1,963 2,042

2,063

Summer

1,763

1,690

1,755

1,731

1,844

1,982 2,052

2,079

Winter

198

226

233

219

212

205 220

220

Summer

198

226

233

219

212

205 220

220

Winter

1,135

1,158

1,142

1,143

1,048

1,034 1,172

1,147

Summer

1,144

1,159

1,149

1,151

1,054

1,040 1,178

1,148

Winter

45 58

Summer

49 58

Winter

66 71

Summer

68 73

Winter

1,655

1,614

1,546

1,482

1,452

1,414 1,611

1,543

Summer

1,712

1,663

1,583

1,524

1,509

1,469 1,763

1,689

Winter

51 58

Summer

51 58

Winter

79 75

Summer

85 81

Winter

818

723

887

856

599

670 802

1,038

Summer

818

725

888

856

600

671 802

1,038

18 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Table 2. Populations who use domestic self-supply wells in Rhode Island by 12-digit hydrologic unit code (HUC12) subwatershed for calendar years 2014–2021.—Continued

Table 2. Populations who use domestic self-supply wells in Rhode Island by 12-digit hydrologic unit code (HUC12) subwatershed for calendar years 2014–2021.—Continued [Data from Chamberlin and Armstrong (2024). HUC12s from U.S. Geological Survey (2020), accessed with nhdplusTools (Blodgett and Johnson, 2023). Map labels correspond to labels on figure 10. Winter is defined as January 1 to March 31 and October 1 to December 31; summer is defined as April 1 to September 30. —, no data]

Map label

Subwatershed name

HUC12

Percent of subwatershed in Rhode Island

Population per calendar year Season

2014

2015

2016

2017

2018

2019

2020

2021

Narragansett Bay drainage basin—Continued 28 29 30 31

Hunt River Mount Hope Bay Upper West Passage Upper East Passage

010900040904 010900040905 010900040906 010900040907

100 21 30 53

Lower West Passage

010900040908

Lower East Passage

010900040909

Sakonnet River

010900040910

Aquidneck Island-Frontal Atlantic Ocean

010900040911

Pettaquamscutt RiverFrontal Atlantic Ocean

010900040912

Upper Wood River

010900050101

Lower Wood River

010900050102

Winter

1,257

1,206

1,262

1,247

1,303

1,248

1,265

1,213

Summer

1,281

1,234

1,288

1,276

1,333

1,259

1,327

1,276

Winter

2,028

2,154

2,231

2,338

2,428

2,461

1,913

2,270

Summer

2,072

2,184

2,258

2,371

2,455

2,488

1,928

2,302

Winter

Summer

Winter

353

290

319

318

325

315

510

497

Summer

399

330

351

348

351

347

554

541

Winter

2,029

2,098

2,358

2,375

2,538

2,451

2,282

2,071

Summer

2,400

2,476

2,626

2,667

2,800

2,560

2,693

2,635

Winter

1,805

1,478

1,339

1,190

1,124

1,155

1,369

1,694

Summer

2,247

1,833

1,626

1,445

1,221

1,275

1,561

1,927

Winter

3,830

3,915

3,890

3,833

3,892

3,673

3,768

3,401

Summer

4,432

4,655

4,502

4,563

4,728

4,545

5,109

4,502

Winter

Summer

Winter

557

543

548

561

571

625

677

Summer

608

582

594

604

609

615

679

736

Pawcatuck River-Wood River drainage basin

010900050201

Usquepaug River

010900050202

Beaver River

010900050203

100 100 100

5,956

5,926

5,863

5,391

5,279

5,120

5,344

4,992

Summer

6,075

6,029

5,975

5,532

5,519

5,313

5,559

5,134

Winter

3,479

3,570

3,633

3,610

3,573

3,595

3,629

3,438

Summer

3,579

3,686

3,757

3,643

3,764

3,744

3,825

3,618

Winter

1,248

1,299

1,322

1,355

1,317

1,429

1,394

1,461

Summer

1,253

1,304

1,330

1,363

1,338

1,453

1,419

1,484

Winter

4,714

4,580

4,779

4,978

5,161

5,080

4,833

5,527

Summer

4,782

4,611

4,816

5,017

5,243

5,160

4,919

5,640

Winter

1,857

1,858

1,854

1,935

1,959

2,051

1,938

2,272

Summer

1,930

1,922

1,909

2,001

2,040

2,117

2,012

2,372

Results 19

Chipuxet River-Pawcatuck River

Winter

Map label

Subwatershed name

HUC12

Percent of subwatershed in Rhode Island

Population per calendar year Season

2014

2015

2016

2017

2018

2019

2020

2021

Pawcatuck River-Wood River drainage basin—Continued 42 43 44 45

Usquepaug RiverPawcatuck River

010900050204

Tomaquag BrookPawcatuck River

010900050205

Ashaway River

010900050301

Outlet Pawcatuck River

010900050303

100 100 17 52

Saugatucket River

010900050401

100

Point Judith Pond-Frontal Block Island Sound

010900050402

100

Ninigret Pond-Frontal Block Island Sound

010900050403

Block Island

010900050404

Winter

4,474

4,382

4,373

4,479

4,601

4,821

4,691

4,848

Summer

4,705

4,740

4,728

4,844

5,109

5,237

4,941

5,131

Winter

6,404

6,554

6,611

6,559

6,657

6,318

6,773

6,785

Summer

6,641

6,898

7,040

7,100

7,211

6,991

7,401

Winter

916

903

889

956

974

995

960

1,041

Summer

936

925

933

993

994

1,044

1,040

1,106

Winter

Summer

Winter

257

263

264

275

261

253

289

Summer

259

263

265

278

263

264

257

293

Winter

169

172

166

160

150

156

150

Summer

288

295

297

303

288

304

274

276

Winter

3,845

3,769

3,819

3,776

3,727

3,682

4,147

3,938

Summer

6,425

6,593

6,546

6,330

6,360

6,322

7,083

6,789

Winter

531

536

525

494

483

535

851

601

Summer

2,329

2,302

2,168

2,187

2,216

2,305

7,016

2,454

Quinebaug River drainage basin 50

Upper Fivemile River

011000010301

Lower Fivemile River

011000010302

Upper Moosup River

011000010501

53 54 —

Quaduck Brook Upper Pachaug River Rhode Island

011000010502 011000010601 —

32 4 —

Winter

665

671

680

686

800

757

682

796

Summer

715

725

751

764

851

883

774

884

Winter

333

329

335

391

383

333

408

Summer

350

349

356

366

409

420

367

441

Winter

2,654

2,623

2,658

2,745

2,474

2,574

2,659

2,678

Summer

2,673

2,646

2,676

2,764

2,505

2,587

2,682

2,706

Winter

621

549

555

585

514

557

531

615

Summer

626

554

559

590

519

557

531

615

Winter

Summer

117,044

117,409

116,925

117,057

117,337

117,625

125,323

122,059

Winter

108,192

107,985

107,781

107,729

107,419

107,435

109,658

110,745

20 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Table 2. Populations who use domestic self-supply wells in Rhode Island by 12-digit hydrologic unit code (HUC12) subwatershed for calendar years 2014–2021.—Continued

Results 21

Daily per capita domestic water use rates, in gallons per capita per day

200

150

100

0 2014

2015

2016

2017

Year

2018

2019

2020

2021

EXPLANATION 90th percentile 75th percentile 50th percentile (median) 25th percentile 10th percentile Outlier

Figure 9. Graph showing daily per capita domestic water use coefficients by month in Rhode Island for 2014–21. Rates from Chamberlin and Armstrong (2024).

2022

22 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21 −71°50'

−71°40'

−71°30'

Woonsocket

7 5

−71°10'

EXPLANATION Domestic self-supplied water withdrawal for July 2019–June 2020, in million gallons per day 0.00 to 0.07 Taunton

Attleboro

50 4 12

0.08 to 0.15

0.16 to 0.23

16 41°50'

0.24 to 0.30 0.31 to 0.38

Providence

HUC12 subwatershed boundary Rhode Island State boundary Somerset Town

West Warwick 15

Bristol

30 Narragansett 31 Bay 30

29 24

1 34

33 32 46 Kingston

New Bedford Bliss Corner

41°30'

Fall River

Map label—Corresponds to HUC12 subwatersheds shown on tables 2 and 4

41°40'

−70°50'

−71°

42°

−71°20'

35 Newport

44 39

42 43 Westerly

Narragansett Pier

47 48

45 41°20'

41°10'

49 New Shoreham

0 0

5 5

10 10

15 MILES

15 KILOMETERS

Block Island Base from U.S. Geological Survey National Hydrography Dataset, 1:500,000 Rhode Island State Plane Coordinate System North American Datum of 1983

Figure 10. Map of domestic self-supply water withdrawals in Rhode Island for fiscal year 2020 (July 2019–June 2020) for 12-digit hydrologic unit code (HUC12) subwatersheds. Data from Chamberlin and Armstrong (2024).

Results 23 Table 3. Annual domestic self-supply water withdrawals by municipality in Rhode Island for fiscal years 2015–21 (July 2014– June 2021). [Data from Chamberlin and Armstrong (2024). Fiscal year is defined as the 12-month period from July 1 to June 30 and designated by the calendar year in which it ends. Mgal/d, million gallons per day]

Municipality

Water withdrawals per fiscal year in Mgal/d 2015

2016

2017

2018

2019

2020

2021

Barrington

0.004

0.003

0.004

Bristol

0.084

0.088

0.093

0.094

0.097

0.087

0.081

Burrillville

0.312

0.308

0.262

0.259

0.285

0.316

0.341

Central Falls

Charlestown

0.466

0.461

0.47

0.442

0.416

0.457

0.357

Coventry

0.424

0.432

0.386

0.365

0.38

0.37

0.437

Cranston

0.068

0.06

0.061

0.069

Cumberland

0.06

0.059

0.057

0.054

0.05

0.055

East Greenwich

0.051

0.053

0.051

0.049

0.052

0.047

0.053

East Providence

0.002

Exeter

0.347

0.338

0.315

0.321

0.295

0.285

0.309

Foster

0.197

0.193

0.2

0.205

0.168

0.183

0.202

Glocester

0.387

0.388

0.366

0.352

0.369

0.394

0.423

Hopkinton

0.466

0.44

0.425

0.414

0.364

0.395

0.375

Jamestown

0.139

0.132

0.137

0.13

0.133

0.127

0.148

Johnston

0.09

0.093

0.089

0.078

0.08

0.076

0.081

Lincoln

0.004

0.003

0.004

Little Compton

0.203

0.197

0.2

0.196

0.2

0.205

0.236

Middletown

0.093

0.081

0.079

0.07

0.067

0.065

0.071

Narragansett

0.003

0.002

New Shoreham

0.051

0.035

0.04

0.035

0.037

0.054

Newport

0.004

0.003

0.004

0.006

0.008

North Kingstown

0.059

0.057

0.056

0.059

0.067

North Providence

North Smithfield

0.317

0.319

0.301

0.316

0.333

0.344

0.372

Pawtucket

Portsmouth

0.024

0.022

0.023

0.022

0.025

0.032

Providence

Richmond

0.358

0.342

0.318

0.326

0.292

0.301

0.326

Scituate

0.467

0.463

0.485

0.458

0.443

0.435

0.465

Smithfield

0.177

0.174

0.182

0.167

0.172

0.167

0.179

South Kingstown

0.145

0.148

0.15

0.152

0.153

0.17

0.178

Tiverton

0.218

0.165

0.207

0.244

0.246

0.323

0.353

Warren

0.021

0.022

0.018

0.019

0.018

0.019

0.021

Warwick

0.004

0.003

0.004

West Greenwich

0.261

0.263

0.243

0.23

0.225

0.214

0.247

West Warwick

Westerly

0.035

0.033

0.038

0.035

0.031

0.035

0.045

Woonsocket

Rhode Island

5.54

5.4

5.28

5.18

5.06

5.27

5.6

[Data from Chamberlin and Armstrong (2024). HUC12s from U.S. Geological Survey (2020), accessed with nhdplusTools (Blodgett and Johnson, 2023). Map labels correspond to labels on figure 10. Fiscal year is defined as the 12-month period from July 1 to June 30 and designated by the calendar year in which it ends. Mgal/d, million gallons per day; —, no data]

Map label

Subwatershed name

Percent of subwatershed in Rhode Island

HUC12

Water withdrawals per fiscal year in Mgal/d 2015

2016

2017

2018

2019

2020

2021

Cape Cod Bay drainage basin 1

Westport River

010900020502

0.076

0.047

0.07

0.088

0.086

0.123

0.133

Cold Brook-Rhode Island Sound

010900020503

0.142

0.136

0.14

0.137

0.141

0.143

0.164

Clear River

010900030202

0.172

0.17

0.146

0.144

0.153

0.166

0.188

Chepachet River

010900030203

100

0.162

0.143

0.136

0.142

0.163

0.17

Branch River

010900030204

0.269

0.268

0.23

0.231

0.254

0.285

0.311

Mill River

010900030205

Emerson Brook-Blackstone River

010900030206

0.095

0.099

0.096

0.101

0.108

0.109

Abbott Run

010900030207

0.036

0.035

0.033

0.032

0.031

0.033

Peters River-Blackstone River

010900030208

0.066

0.064

0.063

0.061

0.065

0.069

Ten Mile River

010900040401

Blackstone River drainage basin

Narragansett Bay drainage basin 11

Moshassuck River

010900040501

100

0.006

0.007

0.006

0.007

0.008

0.01

Woonasquatucket River

010900040502

100

0.343

0.342

0.352

0.334

0.343

0.33

0.353

Big River

010900040601

100

0.129

0.13

0.12

0.116

0.112

0.111

0.132

Flat River Reservoir

010900040602

100

0.308

0.317

0.286

0.274

0.288

0.28

0.327

South Branch Pawtuxet River

010900040603

100

Moswansicut Pond-Huntinghouse Brook

010900040604

100

0.286

0.277

0.288

0.273

0.257

0.246

0.26

Barden Reservoir-Ponaganset River

010900040605

100

0.143

0.134

0.137

0.139

0.113

0.134

0.145

Scituate Reservoir

010900040606

100

0.227

0.233

0.241

0.226

0.221

0.233

North Branch Pawtuxet River

010900040607

100

0.084

0.085

0.082

0.079

0.088

0.089

0.101

Pocasset River

010900040608

100

0.012

0.013

0.011

Pawtuxet River

010900040609

100

0.049

0.044

0.043

0.048

Palmer River

010900040701

0.004

0.003

0.002

0.003

Barrington River-Warren River

010900040702

0.003

0.004

Quequechan River

010900040803

0.073

0.059

0.066

0.071

0.102

0.119

Seekonk River-Providence River

010900040901

0.003

0.002

0.003

Old Mill Creek-Narragansett Bay

010900040902

0.004

0.003

0.004

Greenwich Bay

010900040903

0.003

0.002

0.003

Hunt River

010900040904

100

0.07

0.072

0.069

0.067

0.069

0.064

0.074

24 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

Table 4. Annual domestic self-supply water withdrawals by 12-digit hydrologic unit code (HUC12) subwatershed in Rhode Island for fiscal years 2015–21 (July 2014–June 2021).

Table 4. Annual domestic self-supply water withdrawals by 12-digit hydrologic unit code (HUC12) subwatershed in Rhode Island for fiscal years 2015–21 (July 2014– June 2021).—Continued [Data from Chamberlin and Armstrong (2024). HUC12s from U.S. Geological Survey (2020), accessed with nhdplusTools (Blodgett and Johnson, 2023). Map labels correspond to labels on figure 10. Fiscal year is defined as the 12-month period from July 1 to June 30 and designated by the calendar year in which it ends. Mgal/d, million gallons per day; —, no data]

Map label

Subwatershed name

Percent of subwatershed in Rhode Island

HUC12

Water withdrawals per fiscal year in Mgal/d 2015

2016

2017

2018

2019

2020

2021

Narragansett Bay drainage basin—Continued 29

Mount Hope Bay

010900040905

0.097

0.102

0.103

0.106

0.109

0.098

0.095

Upper West Passage

010900040906

0.003

0.002

0.003

Upper East Passage

010900040907

0.016

0.015

0.016

0.015

0.018

0.025

Lower West Passage

010900040908

0.104

0.105

0.114

0.113

0.116

0.107

0.112

Lower East Passage

010900040909

0.084

0.068

0.063

0.054

0.052

0.055

0.073

Sakonnet River

010900040910

0.192

0.178

0.189

0.196

0.2

0.21

0.229

Aquidneck Island-Frontal Atlantic Ocean

010900040911

0.001

0.002

Pettaquamscutt River-Frontal Atlantic Ocean

010900040912

0.028

0.027

0.03

0.033

Upper Wood River

010900050101

Lower Wood River

Chipuxet River-Pawcatuck River

40 41

Pawcatuck River-Wood River drainage basin 86

0.353

0.341

0.298

0.287

0.259

0.251

0.275

010900050102

0.201

0.196

0.182

0.185

0.164

0.165

0.169

010900050201

100

0.062

0.063

0.064

0.063

0.069

Usquepaug River

010900050202

100

0.264

0.258

0.246

0.258

0.241

0.227

0.259

Beaver River

010900050203

100

0.11

0.104

0.097

0.103

0.091

0.09

0.102

Usquepaug River-Pawcatuck River

010900050204

100

0.225

0.221

0.219

0.221

0.225

0.24

0.235

Tomaquag Brook-Pawcatuck River

010900050205

100

0.405

0.391

0.404

0.382

0.341

0.38

0.347

Ashaway River

010900050301

0.059

0.054

0.056

0.055

0.049

0.056

0.051

Outlet Pawcatuck River

010900050303

0.001

Saugatucket River

010900050401

100

0.013

0.012

0.013

Point Judith Pond-Frontal Block Island Sound

010900050402

100

0.011

0.01

0.011

Ninigret Pond-Frontal Block Island Sound

010900050403

0.283

0.28

0.283

0.259

0.244

0.277

0.212

Block Island

010900050404

0.051

0.035

0.04

0.035

0.037

0.054

Upper Fivemile River

011000010301

0.026

0.027

0.023

0.025

0.028

0.029

0.032

Lower Fivemile River

011000010302

0.013

0.012

0.011

0.012

0.014

0.016

Upper Moosup River

011000010501

0.146

0.15

0.144

0.137

0.13

0.152

Quaduck Brook

011000010502

0.025

0.022

0.024

0.026

0.019

0.022

0.025

Upper Pachaug River

011000010601

0.001

—

5.54

5.4

5.28

5.18

5.06

5.27

5.6

Quinebaug River drainage basin

Rhode Island

Results 25

—

Total domestic self-supplied water withdrawal rates for Rhode Island, in million gallons per day

26 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

0 2014

2015

2016

2017

2018

2019

2020

2021

2022

Year

Figure 11. Graph showing time series of total domestic water withdrawals from self-supply wells in Rhode Island for 2014–21. Data from Chamberlin and Armstrong (2024).

Discussion The estimates of domestic self-supply water withdrawals from private wells are largest in rural, less populated parts of the State. Self-supply withdrawals are generally highest in summer, when water use per capita is highest (largely due to increased water use for outdoor purposes, such as irrigating lawns, maintaining swimming pools, and watering gardens) and when populations increase in areas popular for summer tourism. Self-supply withdrawals appear to be largely consistent over the period of this study (July 2014– June 2021), though the population of Rhode Island increased over this time, especially after 2019. Statewide, domestic self-supply water withdrawal is a small fraction of the State’s water budget: summer peak withdrawals were <8 Mgal/d, as compared with an estimated 120 Mgal/d for summer averages from all reported and estimated public-supply withdrawals (Rhode Island Water Resources Board, 2022). Locally, however, domestic self-supply wells may be the

largest source of water withdrawal within a municipality or subwatershed (HUC12), and providing this previously unavailable information can assist with planning in these areas. Additionally, periods of high withdrawal frequently correspond to periods of low groundwater levels during hot and dry summers. Our estimates of the domestic self-supply population are compatible with estimates for Rhode Island from other national and regional studies. Using two methods to estimate housing units using domestic self-supply wells in 2010, Murray and others (2021) produced estimates of roughly 10,000 housing units (based on the number of reported wells) and 60,000 housing units (based on the net housing units). With an average of 2.43 people per household for 2018–22 (Manson and others, 2023), 10,000 to 60,000 housing units is equivalent to 24,300–145,800 people who use domestic self-supply wells. Johnson and others (2019) estimated the population who use self-supply wells in Rhode Island to be 100,001 to 250,000 people in 2010. This

Conclusions 27 study estimated 107,419–125,323 people served by domestic self-supply wells in the State between 2014 and 2021. The wide ranges of estimates in Murray and others (2021) and Johnson and others (2019) demonstrate the difficulty of precisely estimating domestic self-supply and why smaller scale studies, such as this one, can be useful in generating more precise local estimates. At the drainage basin scale, the results of this study were similar to estimates from a 1995–99 study (Wild and Nimiroski, 2007). In drainage basins that overlap between the two studies, we estimated an average of 23,890 people who use self-supply wells in the Pawtuxet River drainage basin6 (compared with 26,784 people in Wild and Nimiroski [2007]) and 4,360 people in the Quinebaug River drainage basin7 (compared with 4,501 people; Quinebaug River not shown on any map). The decrease in the population who use self-supply wells from 1995–99 to the period described in this study is consistent with the negative population change coefficients seen between 2014 and 2021 for many census block groups in the interior western parts of the State (fig. 5). Wild and Nimiroski (2007) also estimated water withdrawal from domestic self-supply wells in the Pawtuxet River and Quinebaug River drainage basins. Though different methods were used to estimate withdrawal in this study, our results are largely consistent with their estimates from the 1990s and overall trends. Wild and Nimiroski (2007) constructed detailed water budgets of the Pawtuxet River drainage basin and Rhode Island portions of the Quinebaug River drainage basin and estimated annual domestic self-supply withdrawals of 1.915 Mgal/d for the Pawtuxet River drainage basin and 0.319 Mgal/d for the Quinebaug River drainage basin. Over the time period of this study (20 years after the study period of Wild and Nimiroski [2007]), we estimated average annual domestic self-supply withdrawals of 1.198 Mgal/d for the Pawtuxet River drainage basin and 0.205 Mgal/d for the Quinebaug River drainage basin. The decreases in water withdrawals are consistent with a decrease in population in the drainage basins and also decreases of the per capita water use coefficients. Nationally, domestic water use has been declining because of many factors, including technological advancements and government policies (DeOreo and Mayer, 2012; Dieter and others, 2018). Wild and Nimiroski (2007) used per capita water use coefficients of 71 gallons per person per day, whereas the calculated per capita water use coefficients in this study were typically less than this value (fig. 9).

6HUC12s 010900040601, 010900040602, 010900040603, 010900040604, 010900040605, 010900040606, 010900040607, 010900040608, and 010900040609. 7HUC12s 011000010301, 011000010302, 011000010501, 011000010502, and 011000010601.

Conclusions Understanding the spatial and temporal distribution of water withdrawals from private domestic wells is necessary for a complete accounting of domestic water withdrawals throughout Rhode Island. This understanding is also important because of the greater potential for drinking water contamination in private wells as a result of increased vulnerabilities and lower testing requirements (DeSimone and others 2014). Water withdrawal through private wells in Rhode Island occurs primarily in the western parts of the State. The spatial patterns closely correspond to the estimates of population density in areas not served by public water supply. The U.S. Geological Survey, in cooperation with the Rhode Island Water Resources Board, found that water withdrawals through private wells account for a small portion of the State’s total domestic water withdrawals and that, statewide, annual withdrawals have been steady between 2014 and 2021. Though populations who use domestic self-supply wells have increased in Rhode Island between 2014 and 2021, and though substantial seasonal fluctuation in the domestic self-supply population exists, there have been no statistically significant annual or seasonal trends in domestic self-supply water withdrawals between 2014 and 2021. Withdrawals from private wells are largest in the inland areas of the western part of the State, and the towns of Scituate and Charlestown have the highest estimated withdrawals. Statewide withdrawals ranged from 3.987 to 7.767 million gallons per day over the study period. The median per capita domestic water use rate was 46.0 gallons per capita per day. With the estimates from this study, water-budget and availability of individual basins can be studied in more detail. This study produced newly available monthly and annual 30-meter dasymetric rasters of estimates of populations who rely on domestic self-supply wells and water withdrawal from these wells for the state of Rhode Island. These products complement the withdrawal and population information currently available for domestic water use for public water systems. The combination of these products may assist water managers and planners in providing estimates of total withdrawal for domestic use at any spatial resolution, including subwatersheds, municipality boundaries, or counties. As water demands from future development projects are considered, a unified and complete estimate of current and historical water withdrawals for domestic use can be useful for managing Rhode Island’s water resources.

28 Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

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For more information about this report, contact: Director, New England Water Science Center U.S. Geological Survey 10 Bearfoot Road Northborough, MA 01532 dc_[email protected] or visit our website at https://www.usgs.gov/centers/new-england-water Publishing support provided by the Pembroke Publishing Service Center

Chamberlin and others—Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21—SIR 2024–5109

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Estimating Domestic Self-Supplied Water Use in Rhode Island, 2014–21

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