Free Water Quality Reports

What's really in
your tap water?

Instant water quality grades for 29,542 US ZIP codes. Powered by EPA data, PFAS monitoring, and violation records.

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29,542 ZIP Codes
30 PFAS Tested
3.2M Violations Tracked
51 States + DC

National Overview

Water Quality Grades

Every ZIP code receives a grade from A to F based on contaminant levels, PFAS detections, violation history, and enforcement actions.

A
38% 11,187
B
25% 7,327
C
21% 6,328
D
14% 4,119
F
2% 581

Browse by State

All 50 States + DC

A
Hawaii84 ZIPs · Score 95
 B
Nebraska515 ZIPs · Score 90
 B
Minnesota737 ZIPs · Score 88
 B
Iowa837 ZIPs · Score 87
 B
North Dakota339 ZIPs · Score 86
 B
Arkansas540 ZIPs · Score 85
 B
Kentucky680 ZIPs · Score 84
 B
South Dakota332 ZIPs · Score 84
 B
Virginia632 ZIPs · Score 82
 B
Tennessee602 ZIPs · Score 81
 B
Massachusetts547 ZIPs · Score 81
 B
South Carolina399 ZIPs · Score 81
 B
Ohio1055 ZIPs · Score 81
 B
California1716 ZIPs · Score 81
 B
Missouri887 ZIPs · Score 80
 B
Indiana654 ZIPs · Score 79
 B
Michigan777 ZIPs · Score 78
 B
Wisconsin627 ZIPs · Score 78
 B
Nevada165 ZIPs · Score 78
 B
Louisiana517 ZIPs · Score 78
 B
Maryland357 ZIPs · Score 77
 B
New Hampshire184 ZIPs · Score 77
 B
Delaware62 ZIPs · Score 77
 B
Georgia735 ZIPs · Score 77
 B
Vermont182 ZIPs · Score 76
 B
Maine216 ZIPs · Score 76
 B
Washington500 ZIPs · Score 76
 B
Kansas638 ZIPs · Score 75
 B
Montana240 ZIPs · Score 75
 C
New York1475 ZIPs · Score 75
 C
Illinois1259 ZIPs · Score 74
 C
Utah263 ZIPs · Score 74
 C
Wyoming125 ZIPs · Score 74
 C
North Carolina811 ZIPs · Score 72
 C
Alabama637 ZIPs · Score 70
 C
District of Columbia268 ZIPs · Score 70
 C
Connecticut265 ZIPs · Score 69
 C
Idaho235 ZIPs · Score 69
 C
Texas1905 ZIPs · Score 68
 C
New Mexico291 ZIPs · Score 68
 C
West Virginia474 ZIPs · Score 67
 C
Oregon347 ZIPs · Score 67
 C
Colorado461 ZIPs · Score 65
 C
Mississippi436 ZIPs · Score 65
 C
Pennsylvania1418 ZIPs · Score 63
 C
Florida1016 ZIPs · Score 63
 C
New Jersey557 ZIPs · Score 62
 C
Rhode Island68 ZIPs · Score 62
 D
Arizona385 ZIPs · Score 60
 D
Oklahoma627 ZIPs · Score 59
 D
Alaska201 ZIPs · Score 54

About This Data

US Water Score aggregates publicly available water quality data from the EPA's Safe Drinking Water Information System (SDWIS), the Unregulated Contaminant Monitoring Rule (UCMR5) for PFAS, and enforcement records. We analyze data from over 96,000 community water systems serving 300+ million Americans. Data was last updated in March 2026.

Our Methodology

Each ZIP code is scored 0–100 using a weighted algorithm: violation count and severity (log-scaled, 30% weight), lead 90th percentile levels vs. EPA action level of 15 ppb (25% weight), copper 90th percentile levels vs. 1,300 ppb action level (10% weight), PFAS detections and MCL exceedances from UCMR5 data (20% weight), and enforcement actions (15% weight). Letter grades map as: A (85–100), B (70–84), C (55–69), D (35–54), F (0–34). ZIP codes are linked to water systems via EPA geographic area records, UCMR5 ZIP crosswalk, and Census ZCTA boundary files.

Disclaimer

This site provides water quality information for educational purposes only. Data may not reflect current conditions. Always contact your local water utility or review your annual Consumer Confidence Report for the most up-to-date information. This is not medical or legal advice.