PFAS: Per- and polyfluoroalkyl substances

PFAS are chemicals that resist grease, oil, water, and heat. They were first used in the 1940's and are now in hundreds of products including stain- and water-resistant fabrics and carpeting, cleaning products, paints, and fire-fighting foams.

Milwaukee Water Works closely monitors our water quality. Since 2008, we have regularly tested our water for several PFAS compounds. We test the Lake Michigan source water, the water at our Linnwood and Howard water purification facilities, and the water in our distribution system (nearly 2,000 miles of water mains) at two sites in City of Milwaukee. 

We send all water samples to an external laboratory for analysis. Results from the lab are accompanied by a "detection limit" and a "reporting limit." These values help to determine how confident we can be in the results because it is more and more difficult to precisely measure these compounds the lower the concentration.

The data on this page are focused on test results that come back at or above the reporting limit, because that is the level at which we are most confident in the accuracy of the data. If a compound is listed as "below the reporting limit", that doesn’t always mean it wasn’t detected. "Below the reporting limit" means that if a compound was detected, the concentration was below a level that we can confidently determine.

For more information about Milwaukee Water Works PFAS testing, please leave a message for our Water Quality hotline at 414-286-2585. Include your name, address and phone number in your message. 

In 2023, Milwawaukee Water Works collected quarterly samples in compliance with the Environmental Protection Agency's Unregulated Contaminant Monitoring Rule (UCMR-5). The sampling dates were: 2/20/23, 6/12/23, 8/4/23 and 11/13/23. The EPA set standardized reporting limits for all 29 PFAS compound that were tested. All results were below those reporting limits. The list of compounds tested for this project is below.

For more information on the EPA's Unregulated Contaminant Monitoring Rule (UCMR) 5, go here.   

As of 7/11/24, the EPA has started posting a quarterly update of their UCMR 5 data. This provides any Milwaukee Water Works customers or other interested parties with an opportunity to confirm our results and/or compare them to other utilities. (Note: all Milwaukee Water Works samples were below the standardized reporting limits set by the EPA.)

The results below are from Milwaukee Water Works' annual voluntary PFAS sampling conducted in 2023. 

The table below lists PFAS compunds with results below the reporting limit in 2023. These samples were collected as part of Milwaukee Water Works' voluntary annual sampling. 

PFAS testing data for previous years is available upon request. 

Milwaukee Water Works is committed to providing our customers with safe, clean, drinking water. As your water supplier, we will continue to work closely with DNR and the EPA to maintain the quality of your water. Additional PFAS health information can be found at www.dhs.wisconsin.gov/chemical/pfas.htm.

Frequently Asked Questions about PFAS

What is PFAS?

PFAS stands for Perfluoroalkyl and Polyfluoroalkyl Substances. It is a large group of chemicals used in industry and consumer products since the 1950’s. They have been widely used because of their ability to resist water, grease and heat while remaining chemically stable. Unfortunately, this stability means that they don’t break down easily in the environment, and can accumulate over time.

Are PFAS dangerous to humans?

Yes, over time humans can accumulate enough PFAS in their bodies to increase their risk of several health effects, including increased cholesterol levels, decreased antibody response to vaccines, increased risk of thyroid disease and decreased fertility in women. Humans can be exposed to PFAS through many sources, including food, water, packaging and cosmetics. 

How do PFAS get into the water?

There are many ways that PFAS can be washed into or discharged into our lakes and rivers. One of the most common ways is storm runoff near airports and military bases. PFAS has been commonly used in firefighting foam, so higher concentrations have been found in waterways near these facilities where regular firefighting training exercises take place. PFAS infiltration can also happen from landfills and industrial discharges.

Why are PFAS in the news so much lately?

When PFAS first started to be produced and used in the 1950’s, we didn’t know that they could accumulate in our environment and in our bodies, or that they could cause negative health effects. There has been a lot of new research on PFAS and their health effects in recent years. As more research is done, new regulations are created to address this problem. When there are new steps in the regulatory process or new research articles published, sometimes this catches the attention of reporters and media outlets.

What concentrations of PFAS are dangerous?

This is an area of ongoing research and debate. In 2016, the EPA (Environmental Protection Agency) reviewed existing research and published a health advisory level of 70 ppt (parts per trillion) for two common PFAS compounds (PFOA and PFOS). Since then, more research has found health effects at lower levels. The WDNR suggested drinking water standards of 20 ppt for PFOA and PFOS in 2022, but the Natural Resources Board only approved 70 ppt based on EPA guidance. Later in 2022, the EPA announced new health advisory levels based on the most recent research. Some of these new health advisories are lower concentrations than can be measured with current laboratory instruments and technologies. This is part of the EPA’s rule making process, and some of these levels may change as the process progresses.

PFAS Quarterly Testing Results - 2022

Required Quarterly Sampling, 4th Quarter, 2022: 


Annual 2022 Sampling: