Water Data Tool

Community Water System Service Area Boundaries

This dataset contains geographic service area boundaries for U.S. Community Water Systems in the U.S. and select territories (Puerto Rico, Guam, Northern Mariana Islands). As of October 2025, over half of the approximately 50,000 water system boundaries come from authoritative data sources.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 1/27/2026

Update frequency: Annually

Things you should know

For many systems, this dataset uses modeled boundaries that approximate, not confirm, the true service area of a water system
Modeled areas are derived from population and infrastructure inference methods
Overlapping boundaries may occur between neighboring systems
Some boundaries map to multiple water system IDs
Releases generally occur annually but have come more frequently

Safe Drinking Water Information System

Water system violation, enforcement, and system information submitted by states and utilities.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/20/2026

Update frequency: Quarterly

Things you should know

Several variables in SDWIS reflect regulatory reporting structures rather than underlying infrastructure conditions
Violations are known to be underreported and vary with enforcement practices
In some instances, system age represents the first regulatory record rather than the construction date
The maximum age of any system in this dataset is 45 years due to data reporting beginning in 1979

U.S. Census

The dataset combines 2021 American Community Survey (ACS) demographic and socioeconomic estimates with EPA drinking water system service area boundaries. EPIC allocated ACS census variables to system service areas using spatial crosswalk methods based on EPA boundary files. The result is a set of estimated community characteristics for each drinking water system, not direct measurements of the populations served.

Data source: U.S. Census Bureau

Last updated: 2/2/2026

Update frequency: Annually

Things you should know

Values are statistical estimates and include uncertainty
Population characteristics are modeled using an EPA crosswalk rather than statistics observed at the system level
Income fields are interpolated estimates derived between known values
Results represent characteristics of the estimated service population, not confirmed customer records

National Pollutant Discharge Elimination System (NPDES) Permits

This dataset includes permitted discharge outfalls from the EPA National Pollutant Discharge Elimination System (NPDES). NPDES documents point-source pollutant discharges to surface waters under the Clean Water Act. EPIC links permitted discharge locations to nearby drinking water systems to identify potential upstream pollution pressures. The dataset reflects regulated discharge activity, not measured drinking water contamination or human exposure.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

This dataset indicates the presence of regulated discharges, not contamination at a drinking water intake
Water system treatment processes may remove pollutants
A single permitted facility may appear in multiple watersheds due to multiple outfalls
Violation records reflect regulatory compliance status, not magnitude of pollutant transport
EPIC is working to pinpoint specific features in violation for future tool updates

303(d) Impaired Waterways

This dataset contains impaired surface waters reported by states to EPA under Clean Water Act Sections 303(d) and 305(b) through the Integrated Report. States identify assessment units that do not meet one or more designated water quality uses and require corrective action. EPIC links impaired waters to nearby drinking water systems as a potential indicator of source water characteristics, not treated drinking water quality.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

This dataset represents regulatory impairment status, not contaminant concentrations at drinking water intakes
Listing criteria and assessment coverage vary significantly by state
Drinking water treatment may remove listed pollutants
Not all waters are assessed each cycle
A listed water body does not imply customer exposure or Safe Drinking Water Act violations

Oregon Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Oregon. Provided by the Oregon Public Health Authority.

Data source: Oregon Public Health Authority

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Climate and Economic Justice Screening Tool

Built for Biden's Justice40 initiative, the CEJST uses datasets that are indicators of burdens in eight categories: climate change, energy, health, housing, legacy pollution, transportation, water and wastewater, and workforce development.

Data source: Public Environmental Data Partners

Last updated: 1/29/2026

Update frequency: Quarterly

Things you should know

Data were interpolated using a mix of population, household, and areal interpolation. As a result, some variables for some water systems could not be calculated.

Climate Vulnerability Index

The U.S. Climate Vulnerability Index helps you see which communities face the greatest challenges from the impacts of a changing climate.

Data source: Environmental Defense Fund

Last updated: 1/29/2026

Update frequency: Quarterly

Things you should know

Data were interpolated using a mix of population, household, and areal interpolation. As a result, some variables for some water systems could not be calculated.

Social Vulnerability Index

This SVI tool is a place-based index, database, and mapping application designed to identify and quantify communities experiencing social vulnerability. It uses 16 U.S. Census variables from the 5-year American Community Survey (ACS) to identify communities that may need support before, during, or after disasters.

Data source: Center for Disease Control

Last updated: 1/29/2026

Update frequency: Quarterly

Things you should know

Data were interpolated using a mix of population, household, and areal interpolation. As a result, some variables for some water systems could not be calculated.

Drinking Water State Revolving Funds Awards

These data represent funding awards for drinking water investment and improvement from the Drinking Water State Revolving Fund. Disseminated by states, awards are given largely in the form of loans to communities based on federal allotments and state-based programs.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/20/2026

Update frequency: Annually

Things you should know

This dataset contains downloaded data from EPA's State Revolving Fund Public Portal for federal fiscal years 2021-2025
Principle forgiveness represents "Additional Subsidy Amount", which includes direct principle forgiveness, as well as negative interest rates and grants

Water System Watersheds for Well & Intake Locations

These data show the relationship between a water system, and its source watershed. While data on specific intake locations is private given security concerns, this match between a water system and a watershed is shared by the EPA.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 10/7/2024

Update frequency: Static

Things you should know

This data is static and reflects a snapshot of the information contained in EPA's How's My Waterway

Facilities with Risk Management Plans

These data contains location and facility identification information from EPA's Facility Registry Service (FRS) for the subset of facilities that link to the Risk Management Plan (RMP) System. The Risk Management Plan (RMP) database stores the risk management plans reported by companies that handle, manufacture, use, or store certain flammable or toxic substances.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

This dataset is aimed to communicate potential hazards, rather than an actual risk to drinking water

Underground Storage Tanks

This data provides the attributes and locations of active and closed Underground Storage Tanks (USTs), UST facilities, and UST releases in states as of 2018-2019, US territories as of 2020-2021, and Tribal lands as of 2025.

Data source: U.S. Environmental Protection Agency (EPA)

Last updated: 2/3/2026

Update frequency: Static

Things you should know

Please note this dataset is static, and only contains a snapshot of information from 2018 - 2019.
Because the exact location of underground storage tanks are not provided, it is assumed that facilities with underground storage tanks are close in proximity to the storage tanks they manage.
Both "open" and "temporarily out of service" tanks are included in this calculation to be consistent with EPA standards
This dataset is aimed to communicate potential hazards, rather than an actual risk to drinking water

Percent Change in U.S. Census Variables

This dataset contains the 10-year percent change (2011 ACS vs 2021 ACS) in ~70 different census variables for EPA's Service Area Boundaries. EPIC used the EPA ORD crosswalk and NHGIS crosswalk files to estimate counts for 2011 data, and household-weighted interpolation for income variables.

Data source: U.S. Census Bureau

Last updated: 2/3/2026

Update frequency: Annually

Things you should know

Not all census variables were available for the 2011 ACS 5-year estimate
Water systems with duplicated boundaries could not be calculated (approximately 7 water systems)
For the purposes of the application, percent change is capped at 200%
Income variables were adjusted for inflation using methods identical to the BLS CPI Inflation calculator
Calculated from 5-year ACS estimates from 2011 and 2021. See Github methods & documentation for more details

West Virginia Drinking Water Advisories

Publicly available drinking water advisories for water systems located in West Virginia. Provided by the West Virginia Department of Health and Human Resources.

Data source: WV Department of Health and Human Services

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

New Mexico Drinking Water Advisories

Publicly available drinking water advisories for water systems located in New Mexico. Provided by the New Mexico Environment Department.

Data source: New Mexico Environment Department

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
Please note that if an advisory listed multiple water system IDs, the record was duplicated for each water system
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Ohio Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Ohio. Previously provided by the Ohio Environmental Protection Agency.

Data source: Ohio Environmental Protection Agency

Last updated: 7/30/2025

Update frequency: Static

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
This dataset is no longer being maintained by the state of Ohio
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Rhode Island Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Rhode Island. Provided by the Rhode Island Department of Health.

Data source: Rhode Island Department of Health

Last updated: 7/30/2025

Update frequency: Static

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
The last update of this dataset occurred on July 30th, 2025. Our team is working on updating this dataset
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Washington Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Washington. Provided by the Washington Department of Health.

Data source: Washington Department of Health

Last updated: 2/4/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Missouri Drinking Water Advisories

Publicly available advisories for systems with long-term contaminant issues in Missouri. Provided by the State of Missouri Data Portal.

Data source: State of Missouri Data Portal

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
This is not a comprehensive record, as this dataset only contains advisories from long-term contaminant issues
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Maine Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Maine. Provided by the Maine Department of Health and Human Services.

Data source: Maine Department of Health and Human Services

Last updated: 2/4/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Alaska Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Alaska. Provided by Alaska's Department of Environmental Conservation.

Data source: AK Department of Environmental Conservation

Last updated: 2/4/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Arkansas Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Arkansas. Provided by the Arkansas Department of Health.

Data source: AR Department of Health

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
Please note there was a gap in our data collection from May 21st, 2025 to Feb 3rd, 2026
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Florida Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Florida during extreme weather events. Provided by Florida Health.

Data source: Florida Health

Last updated: 2/3/2026

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
This is not a comprehensive record - Florida only lists advisories declared during a natural disaster, such as a hurricane or tropical weather event
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Massachusetts Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Massachusetts. Provided by Massachusetts Department of Environmental Protection.

Data source: Massachusetts Department of Environmental Protection

Last updated: 10/30/2025

Update frequency: Quarterly

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Louisiana Drinking Water Advisories

Publicly available drinking water advisories for water systems located in Louisiana. Provided by Louisiana Department of Health. Last update was July 9th 2025.

Data source: Louisiana Department of Health

Last updated: 7/9/2025

Update frequency: Static

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
Due to data download limits, this dataset includes system-issued boil water notices from 2024-2025, and state-issued boil water advisories from 2015-2025
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Texas Drinking Water Advisories

FOIA'd drinking water advisories for water systems located in Texas. Provided by the Texas Commission on Environmental Quality.

Data source: Texas Commission on Environmental Quality (TCEQ)

Last updated: 4/17/2024

Update frequency: Static

Things you should know

Data represents historical advisory events, not current drinking water conditions
The official state site should be used for real-time public health information
Advisories include precautionary notices such as boil water alerts, service interruptions, and planned maintenance events, not just contamination incidents
Please note this dataset only contains records from 2018 - 2024 from a FOIA request. Our team is working on updating this dataset
It is assumed that a system would have maximum one advisory on a given day, and advisories that have been edited by the state are considered a distinct advisory

Drinking Water Explorer

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Financial

Funding (2021–2025)

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Socioeconomics

Race/Ethnicity

Vulnerability

Datasets

Community Water System Service Area Boundaries

Safe Drinking Water Information System

U.S. Census

National Pollutant Discharge Elimination System (NPDES) Permits

303(d) Impaired Waterways

Oregon Drinking Water Advisories

Climate and Economic Justice Screening Tool

Climate Vulnerability Index

Social Vulnerability Index

Drinking Water State Revolving Funds Awards

Water System Watersheds for Well & Intake Locations

Facilities with Risk Management Plans

Underground Storage Tanks

Percent Change in U.S. Census Variables

West Virginia Drinking Water Advisories

New Mexico Drinking Water Advisories

Ohio Drinking Water Advisories

Rhode Island Drinking Water Advisories

Washington Drinking Water Advisories

Missouri Drinking Water Advisories

Maine Drinking Water Advisories

Alaska Drinking Water Advisories

Arkansas Drinking Water Advisories

Florida Drinking Water Advisories

Massachusetts Drinking Water Advisories

Louisiana Drinking Water Advisories

Texas Drinking Water Advisories

Documentation

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