Wisconsin Municipal Water Utilities Test for PFAS

And Get Ready for Lower Drinking Water Limits

Wisconsin water utilities’ number one priority is protecting public health.  We work diligently to provide safe, high-quality drinking water that meets all federal and state standards.

The Environmental Protection Agency has recently recommended new national drinking water standards for six chemicals that are part of a large family of man-made chemicals referred to as Per- and Polyfluoroalkyl Substances (PFAS).  Last year, Wisconsin adopted state drinking water standards for two of these six chemicals.

We want to tell you about these PFAS standards and what we are doing to deliver you safe, high-quality water.

About PFAS

PFAS are a large family of more than 5,000 man-made chemicals that have been used in industry and consumer products since the 1940s because of their useful properties.  There are thousands of different PFAS, some of which have been more widely used and studied than others.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two of the most widely used and studied chemicals in the PFAS group.  According to EPA, PFOA and PFOS have been replaced in the United States with other PFAS in recent years. 

A major concern with PFAS chemicals is that they break down very slowly and as a result they can build up in people, animals, and the environment over time.  Because of their widespread use and their persistence in the environment, many PFAS are found in the blood of people and animals all over the world and are present at low levels in a variety of food products and in the environment.  PFAS are found in water, air, fish, and soil at locations across the nation and the globe.

EPA Proposes National Drinking Water Standards for PFAS

On March 14, 2023, EPA proposed national drinking water standards for PFOA and PFOS, and a combination of four other PFAS chemicals (PFNA, HFPO-DA (GenX), PFHxS, and PFBS).  The proposed standards for PFOA and PFOS are 4 parts per trillion.  The proposed standard for the other four PFAS chemicals combined is based on a hazard index of 1.  This is the first time EPA has proposed basing a drinking water standard on a hazard index.

Under EPA’s proposal, the hazard index equals the sum of four fractions  -- one fraction for each PFAS chemical covered by the combined standard.  Each fraction compares the level of the specific PFAS chemical measured in water to the health based level set by EPA for that chemical.  EPA’s proposed health-based levels for the four PFAS in parts per trillion (ppt) are PFHxS at 9 ppt; HFPO-DA (GenX) at 10 ppt; PFNA at 10 ppt; and PFBS at 2000 ppt.  If the sum of the four fractions is greater than 1.0, the proposed hazard index standard would be exceeded.

EPA intends to finalize its national drinking water standards for these PFAS chemicals by the end of 2023.  Once the national rules are finalized, water systems will have three years to meet these limits.

Wisconsin Limits for PFOA and PFOS Currently in Effect

Until national standards are in place, Wisconsin’s adopted drinking water standards for PFOA and PFOS of 70 ppt will continue to apply.  

Wisconsin’s regulation requires all Wisconsin municipal water utilities to test their drinking water for PFOA and PFOS by the end of 2023.  Customers will be notified if their water utility’s PFAS sampling results exceed the state standards or the lower health advisory levels that have been recommended by Wisconsin’s Department of Health Services (DHS).  In addition, all sample results will be included in the utility’s consumer confidence report.

Municipal Water Systems Get Ready for Lower Limits

All municipal water utilities are testing drinking water for PFOA and PFOS now and many are testing for a wider range of PFAS chemicals. The benefit of testing now is that we can know whether a utility’s drinking water will meet the lower national standards or whether steps will need to be taken in the future to meet lower standards.  If steps need to be taken, communities and their customers will have more time to prepare and determine the best path forward.

For More Information

For more information on PFAS and what you can do, visit the websites of the Environmental Protection Agency, the Wisconsin Department of Natural Resources, or the Wisconsin Department of Health Services.