City of Pewaukee water customers have received a new public notice after tests at Well No. 8 showed “forever chemicals” above state maximum contaminant levels, including PFHxS at nearly five times the limit.
The July 31, 2026, Tier 2 notice from the City of Pewaukee Department of Public Works Water & Sewer Utility follows sampling on July 7. Results included PFHxS at 47 parts per trillion (limit: 10 ppt), PFOA at 6.2 ppt (limit: 4), PFOS at 5.8 ppt (limit: 4), and a hazard index of 4.7 (limit: 1.0).
The Wisconsin Department of Natural Resources required the notice. Officials said the results do not yet constitute an Maximum Contaminant Level (MCL) violation; a violation would be issued only if the running annual average still exceeds the limits after April 26, 2029.
Well No. 8, one of the city’s 12 groundwater wells, was first flagged for PFAS in 2023 and briefly taken offline. The city later returned it to limited service and blends it with other wells, saying it needs the extra supply for daily demand and fire protection. A second mixing point, Entry Point 500 (Wells 11 and 12), has also exceeded health advisory levels. Because water from all 12 wells is combined in pipes and towers before it reaches taps, no home is served by a single well, and the notice applies citywide.
The notice states that long-term exposure above the limits may raise risks to the immune system, liver, thyroid, cardiovascular system, cholesterol levels, and development during pregnancy and childhood, and that some PFAS have been linked to certain cancers. PFAS are not readily absorbed through the skin, so showering, bathing, and washing are considered much lower risk than drinking the water.
Boiling does not remove PFAS. The city and DNR recommend certified granular activated carbon filters meeting NSF/ANSI Standard 53, or reverse-osmosis systems that include a GAC component, for drinking and cooking water. Alternative tested water sources are also listed as an option.
The utility has completed a pilot showing anion-exchange treatment can remove PFAS at Well No. 8. Treatment and pump-station designs were submitted to the DNR in late June 2026. Officials expect to bid construction by the end of 2026, with work in 2027. A Safe Drinking Water Loan application has been filed to help pay for the project.
City materials continue to state that the utility is not currently in violation of drinking water standards and that residents may keep using municipal water for bathing and household use. Local social media posts this week, including video of the mailed notice, have circulated urging neighbors to install certified filters before drinking from the tap.
Questions can be directed to Utility Manager Jane Mueller at (262) 691-0804. The full notice is posted on the city’s PFAS information page.
