Arsenic in drinking water
Natural in rock, high in parts of the West, New England and the Midwest.
Health: Known human carcinogen (skin, bladder, lung). Health goal of zero.
Across the US
726 community water systems had at least one health-based Arsenic violation since 2016. Routine Arsenic sample results are reported to states, not to EPA's national database, so this page ranks systems by violations rather than levels.
Most violations
| Water system | People | Violations |
|---|---|---|
| Tri County Special Utility District | 5,353 | 124 |
| Stormlight Mobile Home Park Water System | 76 | 83 |
| Eakly Development Corp Water System | 277 | 82 |
| Tempe Water Supply Corporation 1 | 2,725 | 77 |
| City of Riesel | 1,476 | 69 |
| Duval County Crd Benavides | 2,285 | 62 |
| Eol Water Supply Corporation | 2,103 | 58 |
| Md 42 Still Meadow Water System | 100 | 52 |
| Md 24 Teaford Meadow Lakes Water System | 150 | 50 |
| City of Seagraves | 2,417 | 49 |
| Pb & Sc Water Supply Corporation | 2,163 | 47 |
| Leroy Tours Gerald Water Supply Corporation | 1,845 | 45 |
| Prairie Hill Water Supply Corporation | 2,150 | 42 |
| City of Plains | 1,355 | 42 |
| Axtell Water Supply Corporation | 1,320 | 42 |
| City of New Home | 965 | 42 |
| Victoria County Water Control & Improvement District 2 | 750 | 42 |
| Matagorda County Water Control & Improvement District 2 | 564 | 42 |
| Knoll Enterprises Water System | 500 | 42 |
| Welch Water Supply Corporation | 315 | 42 |
| Bar-Len Mutual Water Company | 126 | 42 |
| Paakweree Village Water Company – Op Association, Inc | 117 | 42 |
| Valley Estates Water System | 68 | 42 |
| Terrells Mobile Home Park Water System | 60 | 42 |
| Grassland Water Supply Corporation | 55 | 42 |
States with the most systems with violations
- California: 126
- Texas: 110
- Arizona: 78
- New Hampshire: 48
- Washington: 29
- Illinois: 28
- Michigan: 27
- Oregon: 24
- New Mexico: 20
- Nevada: 18
- Minnesota: 17
- Idaho: 15
Sources
The limits, health goals and health effects on this page come from these EPA sources. The results come from EPA's monitoring data for each water system.
- EPA: National Primary Drinking Water Regulations (limits and health effects table)
- EPA ECHO: Safe Drinking Water Information System data
This page summarizes public regulatory information. It is not medical advice. How we source and check this site.
Questions
What is the safe level of Arsenic in drinking water?
The federal legal limit (MCL) is 10 ppb. EPA's health goal (MCLG), the level with no known risk, is zero.
How do I remove Arsenic from tap water?
See the filter guidance on this page: look for a product certified for Arsenic specifically, and check the claim in NSF's certified product listings.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.