PFAS Hazard Index in drinking water
A combined limit for mixtures of PFHxS, PFNA, GenX and PFBS. Each is divided by its health-based level and the fractions added up. Above 1 means the mix is too high.
Health: Applies only when at least two of the four are present. PFBS's health-based level is 2,000 ppt and the other three are 10 ppt.
EPA proposed in May 2026 to rescind this limit. The proposal is not final. The April 2024 limit stays on the books until a final rule says otherwise.
Across the US
Those 77 systems serve about 4.6 million people.
From EPA's UCMR 5 testing, 2023–2025: every community system serving 3,300+ people and a sample of smaller ones.
Highest results
| Water system | People | Highest average |
|---|---|---|
| Bayleaf Master Water System | 16,715 | 14 |
| Emmaus Borough Public Water | 14,000 | 11.4 |
| City of Abbeville | 5,650 | 8.14 |
| Running Springs Water District | 5,268 | 6.86 |
| City of Tempe | 165,000 | 6.79 |
| Greenwood Commission of Public Works | 52,022 | 6.28 |
| Saukville Waterworks | 4,268 | 6.26 |
| Yeshiva Farm Settlement Water System | 300 | 5.06 |
| Augusta-Richmond County Water System | 204,000 | 4.45 |
| Emerald Coast Utilities Authority (ECUA) | 242,172 | 4.44 |
| Quistorff Water System | 1,113 | 4.42 |
| City of Great Bend | 14,580 | 4.4 |
| Robeson County Water System | 67,970 | 4.19 |
| City of Belton | 6,762 | 4.19 |
| City of Ocala | 66,449 | 4.15 |
| Capitol Water Corp | 9,000 | 4 |
| Guam Waterworks Authority – Northern Water System | 139,207 | 4 |
| East Greenwich Township Water Dept | 9,900 | 3.67 |
| Laurens County Water & Sewer Commission | 44,866 | 3.51 |
| Pewaukee City Water and Sewer Utility | 8,671 | 3.46 |
| Sauk Rapids Water System | 13,835 | 3.23 |
| Garden City Water and Sewer System | 12,500 | 3.19 |
| City of Moses Lake | 32,428 | 3.18 |
| City of Pflugerville | 63,464 | 3.14 |
| City of Fresno | 545,970 | 3.12 |
All 76 utilities on this site above the PFAS Hazard Index limit, by state
Arizona: City of Tempe, Town of Payson, Marana Municipal – Marana, City of Globe
California: City of Fresno, City of Sacramento Main, California Water Service – Chico, City of Pleasanton, City of Atwater, Big Bear City Community Services District, Crestline Village County Water District – Division 10, City of Gridley, Running Springs Water District, Atascadero State Hospital Water System
Colorado: Widefield Water & Sanitation District
Delaware: Georgetown Water Department
Florida: Emerald Coast Utilities Authority (ECUA), City of Ocala, City of Zephyrhills, Lady Lake Central – Wps 1,2,3 Water System, Lake Panasoffkee Water Association
Georgia: Augusta-Richmond County Water System
Guam: Guam Waterworks Authority – Northern Water System
Idaho: Garden City Water and Sewer System, Capitol Water Corp
Illinois: North Park Public Water District
Indiana: South Bend Water Works
Kansas: Frusi Water Treatment Plant, City of Great Bend
Massachusetts: Sharon Water Dept, Duxbury Water Department
Michigan: Independence Township Water System
Minnesota: Woodbury Water System, Sauk Rapids Water System, Waite Park Water System
North Carolina: Robeson County Water System, Bayleaf Master Water System, Brookwood Community Water System, Town of Nashville
New Jersey: Ho-Ho-Kus Water Dept
New York: Locust Valley Water District, Yeshiva Farm Settlement Water System
Ohio: Wright-Patterson AFB Area B Public Water System
Pennsylvania: Ambler Borough Water Dept, Palmerton Municipal Authority, Beaver Borough Municipal Authority
Puerto Rico: PRASA – Ponce Urbano
South Carolina: Greenwood Commission of Public Works, Laurens County Water & Sewer Commission, City of Belton, City of Abbeville, Donalds-Due West Water & Sewer Authority, Town of Honea Path, Saluda Commission of Public Works
Tennessee: Fort Campbell Water System
Texas: City of Fort Worth, City of Abilene, City of Pflugerville, City of Haltom City, Manville Water Supply Corporation, City of Boerne, Hawley Water Supply Corporation, Potosi Water Supply Corporation, Dyess Air Force Base Water System, Tanglewood on Texoma Water System
Utah: Hildale – Colorado City Water System
Washington: City of Moses Lake, Fairchild Air Force Base Water System, Quistorff Water System
Wisconsin: Pewaukee City Water and Sewer Utility, Saukville Waterworks, Prescott Waterworks
States with the most detections
- Texas: 297
- California: 173
- Florida: 156
- Pennsylvania: 127
- New Jersey: 89
- Alabama: 84
- North Carolina: 81
- Massachusetts: 76
- South Carolina: 69
- Ohio: 65
- Georgia: 64
- Washington: 56
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: Per- and polyfluoroalkyl substances (PFAS) drinking water rule
- EPA: Fifth Unregulated Contaminant Monitoring Rule (UCMR 5)
- EPA: UCMR occurrence data (the test results)
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 PFAS Hazard Index in drinking water?
The federal legal limit (MCL) is 1. EPA's health goal (MCLG), the level with no known risk, is 1. EPA proposed in May 2026 to rescind this limit. The proposal is not final. The April 2024 limit stays on the books until a final rule says otherwise.
How do I remove PFAS Hazard Index from tap water?
See the filter guidance on this page: look for a product certified for PFAS Hazard Index 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.