PFAS and Drinking Water
The Environmental Protection Agency (EPA) sets rules for safe drinking water in the U.S. In Wisconsin, the Department of Natural Resources (DNR) enforces these standards. The La Crosse Water Utility meets or exceeds all requirements and shares testing results with the public to maintain transparency.
PFAS (per- and polyfluoroalkyl substances) are a group of human-made chemicals used since the 1950s. There are thousands of PFAS types, but the most common are PFOA and PFOS.
PFAS can be found in everyday products such as:
- Fast food wrappers
- Disposable coffee cups
- Waterproof or stain-resistant clothing and textiles
Although PFOA and PFOS are no longer widely used, they persist in the environment and can enter surface and groundwater.
EPA Focus Chemicals
- PFOS: Used in stain repellents, carpets, and waterproof clothing
- PFOA: Used in nonstick cookware (such as Teflon™) and textiles
- GenX: A replacement for PFOA, now linked to similar health effects
- PFBS: Used in stain-resistant coatings and industrial processes
Wisconsin PFAS Rules (Effective August 1, 2022)
The DNR established a Maximum Contaminant Level (MCL) of 70 parts per trillion (ppt) for combined PFOA and PFOS. Utilities must regularly test drinking water and take action if levels exceed this limit.
What We’re Doing
- Testing for PFAS quarterly to meet or exceed DNR requirements
- Following EPA and DNR best practices
- Sharing results with the public
- Maintaining water systems to ensure safe drinking water
What You Can Do
Experts recommend reducing PFAS exposure by:
- Avoid relying solely on bottled water (some may contain PFAS)
- Avoid waterproof or stain-resistant textiles
- Transfer food out of packaging and avoid reheating in containers
- Avoid microwave popcorn and many nonstick cookware products
- Use and maintain water filters certified to reduce PFAS
- Avoid products labeled “fluoro-” or PTFE when possible
EPA Updates
April 16, 2024 – New Federal Standards
The EPA established enforceable limits (MCLs) for six PFAS chemicals:
EPA PFAS Maximum Contaminant Levels (MCLs)
| PFAS Chemical |
MCL (parts per trillion) |
| PFOA |
4 |
| PFOS |
4 |
| PFHxS |
10 |
| PFNA |
10 |
| HFPO-DA (GenX) |
10 |
| Mixtures (PFHxS, PFNA, HFPO-DA, PFBS) |
Hazard Index = 1 |
- Monitoring must begin by 2027
- Full compliance is required by 2029
- Current Wisconsin standard (70 ppt for PFOA/PFOS) remains in effect until then
April 4, 2023 – Health Advisory
The EPA issued updated health advisories and proposed limits for six PFAS chemicals.
- Proposed limits for PFOA and PFOS: 4 ppt
- Other PFAS are regulated using a hazard index (combined exposure)
- A hazard index above 1 indicates potential health concern
- Compliance timelines have since been extended (PFOA/PFOS to 2031)