Haloacetic acids (HAA5) in drinking water
A second family of chlorine byproducts.
Health: Long-term exposure increases cancer risk.
Across the US
1,495 community water systems had at least one health-based Haloacetic acids (HAA5) violation since 2016. Routine Haloacetic acids (HAA5) 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 |
|---|---|---|
| Maysville Water System | 1,212 | 58 |
| Muskogee County Rural Water District #5 | 4,135 | 51 |
| Forest Water Supply Corporation | 651 | 50 |
| City of Huxley | 1,930 | 48 |
| City of Lindsay | 12,659 | 45 |
| Barnsdall Water System | 1,243 | 45 |
| Osage County Rural Water District # 5 | 561 | 45 |
| Ryan Utilities Authority | 800 | 43 |
| Fairview Union Water System | 2,346 | 42 |
| Waurika Public Works Authority | 2,100 | 42 |
| Lakewood Water System | 48 | 42 |
| Okmulgee County Rural Water District #1 | 1,890 | 41 |
| Vixen Water System | 750 | 41 |
| Avant Utilities Authority | 361 | 41 |
| Cleveland Municipal Authority | 3,262 | 40 |
| Okmulgee Public Works Authority | 13,495 | 39 |
| Kotzebue Municipal. Water System | 3,234 | 39 |
| Klawock Water System | 904 | 38 |
| Village of Sikes Water System | 639 | 38 |
| Asher Utilities Dev Authority | 375 | 38 |
| Philmont Boy Scout Ranch – Headquarters Water System | 2,000 | 37 |
| Kake Municipal Water | 415 | 37 |
| Pushmataha County Rural Water District #3 | 4,825 | 36 |
| Beggs Public Works Authority | 1,364 | 36 |
| Idabel Public Works Authority | 6,952 | 35 |
States with the most systems with violations
- Oklahoma: 178
- Texas: 158
- Kentucky: 103
- Louisiana: 78
- California: 73
- Kansas: 73
- Florida: 71
- West Virginia: 65
- Pennsylvania: 55
- New York: 51
- North Carolina: 48
- Virginia: 47
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 Haloacetic acids (HAA5) in drinking water?
The federal legal limit (MCL) is 60 ppb.
How do I remove Haloacetic acids (HAA5) from tap water?
See the filter guidance on this page: look for a product certified for Haloacetic acids (HAA5) 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.