Health-based violations
1,513,732
14.3% of total
Public dataset · EPA SDWIS + UCMR5
America’s drinking water,
system by system.
Every Safe Drinking Water Act violation and PFAS test result for 143,076 U.S. public water systems, aggregated from EPA SDWIS and the UCMR5 monitoring program, searchable by system, county, and state.
- 143,076
- Water systems tracked
- 10,559,500
- EPA violations on record
- 1,513,732
- Health-based violations
- 10,252
- Systems PFAS-tested (UCMR5)
The national picture
Of 143,076 U.S. public water systems, 126,455 carry at least one EPA violation, and 34% of the 10,252 systems tested for PFAS came back positive.
- 10,559,500
- Total EPA violations on record
- 1,513,732
- Health-based (MCL / treatment)
- 34%
- UCMR5 systems with PFAS detected
- 66
- States, regions & territories
Counts include both health-based violations (a contaminant exceeded an EPA limit) and the far more common monitoring/reporting violations. Browse the data by state, system, or contaminant below.
Water Quality by State
Browse water systems, violations, and PFAS data for each state.
Alabama
562 systems
98.6% with violations
Alaska
1,326 systems
97.9% with violations
Arizona
1,493 systems
98.4% with violations
Arkansas
1,016 systems
94.5% with violations
California
7,249 systems
89.2% with violations
Colorado
2,193 systems
92.6% with violations
Connecticut
2,332 systems
94% with violations
Delaware
460 systems
74.8% with violations
EPA Region 10 — Tribal Water Systems
158 systems
98.1% with violations
EPA Region 5 — Tribal Water Systems
113 systems
94.7% with violations
EPA Region 8 — Tribal Water Systems
160 systems
96.3% with violations
EPA Region 9 — Tribal Water Systems
323 systems
96.6% with violations
Florida
5,093 systems
93.2% with violations
Georgia
2,382 systems
92.1% with violations
Hawaii
137 systems
80.3% with violations
Idaho
2,005 systems
96.1% with violations
Illinois
5,117 systems
80.8% with violations
Indiana
3,967 systems
95.8% with violations
Iowa
1,795 systems
95.2% with violations
Kansas
957 systems
99.1% with violations
Kentucky
424 systems
99.1% with violations
Louisiana
1,234 systems
92.5% with violations
Maine
1,864 systems
93.6% with violations
Maryland
3,215 systems
79.9% with violations
Massachusetts
1,599 systems
95.2% with violations
Michigan
10,959 systems
86.1% with violations
Minnesota
6,557 systems
Mississippi
1,185 systems
96.1% with violations
Missouri
2,823 systems
95.4% with violations
Montana
2,263 systems
94.7% with violations
Navajo Nation
170 systems
100% with violations
Nebraska
1,309 systems
88.9% with violations
Nevada
589 systems
92.5% with violations
New Hampshire
2,453 systems
90.2% with violations
New Jersey
3,428 systems
95% with violations
New Mexico
1,037 systems
96.9% with violations
New York
8,098 systems
94.4% with violations
North Carolina
5,020 systems
92.9% with violations
North Dakota
368 systems
94% with violations
Ohio
4,181 systems
90.4% with violations
Oklahoma
1,262 systems
98.2% with violations
Oregon
2,518 systems
98.5% with violations
Pennsylvania
7,701 systems
97.1% with violations
Puerto Rico
458 systems
99.6% with violations
Rhode Island
463 systems
95.9% with violations
South Carolina
1,390 systems
South Dakota
654 systems
91.6% with violations
Tennessee
762 systems
94% with violations
Texas
7,351 systems
90.2% with violations
US Virgin Islands
256 systems
83.6% with violations
Utah
1,068 systems
97.6% with violations
Vermont
1,357 systems
93% with violations
Virginia
2,821 systems
90% with violations
Washington
4,557 systems
92.1% with violations
Most Violations
Water systems with the highest number of recorded violations.
#1 Seven Estates Wolfforth, TX
11,570
#2 Pinnacle Water Association Rock, WV
11,356
#3 Coal Mountain Water Coal Mountain, WV
10,707
#4 Congregation Ohr Menachem Canadensis, PA
9,908
#5 Lake Forest Park Water District Lake Forest Park, WA
9,527
#6 Timber Creek MHP East & West McLoud, OK
9,081
#7 Eastside MHP Tuttle, OK
7,572
#8 Skyview Estates Momence, IL
7,512
#9 Circle H MHP Aberdeen, NC
6,905
#10 Salem Heights Estate Lake Ariel, PA
6,572
PFAS Detected
Water systems where PFAS "forever chemicals" were found.
#1 Emmaus Borough Public Water PA
13 PFAS found
#2 Emerald Coast Utilities Authority (Ecua) FL
12 PFAS found
#3 Mdwasa - Main System FL
11 PFAS found
#4 Georgetown Water Department DE
11 PFAS found
#5 Gwa Northern Water System GU
11 PFAS found
#6 North Bay Village, City Of FL
11 PFAS found
#7 Hialeah, City Of FL
11 PFAS found
#8 City of Cameron TX
10 PFAS found
#9 Running Springs Water District CA
10 PFAS found
#10 Great Bend, City Of KS
10 PFAS found
States with the most recorded violations, top 10
Top Highlights
Top 5 Systems by Recorded Violations
Systems tested for PFAS
10,252
3,528 with detections
Share of systems with at least one violation 88.4%
126,455 of 143,076 public water systems
About This Data
PlainWater provides free access to drinking water quality data from the EPA's Safe Drinking Water Information System (SDWIS) and the Fifth Unregulated Contaminant Monitoring Rule (UCMR5) program. Our database covers 143,076 public water systems serving over 347 million Americans, with 10,559,500 recorded violations and 10,252 systems tested for PFAS "forever chemicals."
Drinking Water Guides
Learn how EPA monitors drinking water quality, what PFAS contamination means, and how to check your local water system.
Understanding Water Quality Data
What EPA SDWIS tracks, how violations are classified, and what Maximum Contaminant Levels mean.
PFAS in Drinking Water
What “forever chemicals” are, how UCMR5 monitoring works, and what EPA’s 2024 standards mean for your water system.
How to Check Your Water System
Step-by-step: find your system, read violation reports, check PFAS results, and know what action to take.
Is Your Tap Water Safe?
How to evaluate your tap water: find your system, read violations, check contaminants, and decide on filtration.
PFAS Contamination by State
Which states have the most PFAS detections from UCMR5, why contamination clusters, and the 2024 EPA limits.
About this data
How PlainWater works, and why you can trust these figures
What this site is
PlainWater presents EPA drinking water quality data for public water systems across the United States, merging Safe Drinking Water Act violation history with UCMR5 PFAS ('forever chemical') testing results.
Editorial process
- Source. Download quarterly EPA SDWIS bulk data exports from the ECHO program, covering all public water systems, their violation histories, and system characteristics.
- Verify. Merge UCMR5 PFAS testing results by water system PWSID, showing each detected compound with its measured concentration and EPA health advisory level comparison, exactly as reported.
- Publish. Refresh the database when new quarterly SDWIS exports and UCMR5 results become available, and publish per-system profiles linking back to the EPA source data.
Editorial independence & corrections
The PlainWater editorial team is independent and is not affiliated with the EPA or any state drinking-water program. Found an error or a stale figure? Get in touch via the contact page. See our methodology for full source attribution and known limitations (e.g. UCMR5 only covers systems serving 3,300+ people).
Frequently asked
What data does PlainWater provide?
PlainWater provides EPA drinking water quality data for 143,076 public water systems, 10,559,500 recorded Safe Drinking Water Act violations, and 10,252 systems tested for PFAS under UCMR5, across the United States.
What is PFAS and why does it matter?
PFAS (per- and polyfluoroalkyl substances) are synthetic chemicals found in many water systems. The EPA has set new health-based standards, and PlainWater shows UCMR5 testing results for your area.
Where does the data come from?
Data comes from two EPA sources: the Safe Drinking Water Information System (SDWIS) for violations and the Unregulated Contaminant Monitoring Rule (UCMR5) for PFAS results.
Browse the database
Explore EPA SDWIS and UCMR5 PFAS data by county, state, or contaminant, every page derived directly from the current dataset.
Browse
By County
Drinking-water-system violations and PFAS detections for every US county with EPA SDWIS coverage.
BrowseBy State
State-level rankings of health-based violations and PFAS occurrence rates from EPA SDWIS.
BrowseRankings
SSR-derived leaderboards of US drinking-water systems by violation history.