Perfluorinated Compounds
Madison tap water meets all federal and state standards for drinking water safety.
Per and Polyfluoroalkyl Substances (PFAS)
PFAS, or Per and Polyfluoroalkyl Substances, is a class of thousands of chemicals used in everything from food packaging and cookware to upholstery, clothing and firefighting foam. The chemicals do not break down in the environment and are commonly found in dust, air, soil and water.
Madison Water Utility first began in-depth testing for a broad spectrum of PFAS chemicals at all city wells in 2019 at the urging of community members who petitioned the Water Utility Board for comprehensive monitoring. Testing for PFAS isn’t required by state or federal regulators, and most communities in Wisconsin do not test drinking water for the compounds.
Latest PFAS Test Results
Map of Madison wells
False Positives & Estimated Results
Different types of PFAS compounds
At-home filters
Well 15
PFAS information from Public Health
Latest PFAS Test Results
- At least some PFAS are present in every Madison well, with total amounts ranging from 2.5 to 47 parts-per-trillion.
- All wells in Madison more than meet groundwater standards recently recommended by the WI Dept. of Health Services for 18 types of PFAS compounds.
- PFAS chemicals are not yet regulated in drinking water, but there could be limits established by the State of Wisconsin for some PFAS comounds over the next 1 to 3 years.
View complete 2020 testing results at all operating wells for more than 30 types of PFAS chemicals.
Compare proposed Wisconsin PFAS regulatory limit with levels found in Madison wells.
Compare recommended PFAS groundwater standards with levels found in Madison wells.
To receive all lab reports generated during 2020 PFAS testing (about 300 pages), email water@madisonwater.org
Is Madison's water safe?
Yes, Madison tap water meets all federal and state standards for drinking water safety. If you have special circumstances or want to further purify your water, home filtration (activated carbon filters and reverse osmosis) is an option to reduce PFAS levels.
View map of municipal wells
There are 21 well facilities across Madison that provide the city's water and protect from fires. Wells 15 and 23 are not in service.
Which wells serve your home? Enter your address here to find out
False positives and estimated results
New analytical technology can detect PFAS chemicals down to a fraction of one part-per trillion. But looking for chemicals at such ultra-trace levels means that many detections reported by labs are too low to accurately measure. Levels that are below two parts per-trillion are often reported as estimates. Some results may also be false positives.
Madison Water Utility will test all operating wells again in 2021.
Different types of PFAS compounds
Thousands of types of PFAS chemicals have been manufactured, but a just handful have been well-studied or tied to known health risks. Most drinking water regulation focuses on two types of PFAS compounds called PFOA and PFOS, which have been phased out of use in the United States. Madison Water Utility detected PFOA and/or PFOS in sixteen wells. The estimated level of PFOA + PFOS found ranged from 0.5 to 3.4 parts per trillion. The DNR is considering imposing a safe drinking water limit of 20 parts per trillion for PFOA and PFOS in Wisconsin.
Madison Water Utility also found a broad range of other types of PFAS chemicals during its testing. Most types are not regulated by any state. Others are regulated at much higher levels than PFOA and PFOS.
For example, over 80% of the PFAS detected in Well 9 is a single chemical called PFBA. The most restrictive health-based guideline for PFBA in the United States comes from the Minnesota Department of Health and is set at 7,000 parts-per-trillion. Madison Water Utility found a total PFAS concentration in Well 9 of 47 ppt, with 37 ppt coming from PFBA.
At-home filters
While the very low levels of PFAS found in Madison wells don’t require large-scale wellhead treatment, Madison Water Utility often gets questions about at-home filters. It is possible to reduce PFAS chemicals in water using a home filter. A recent study by Duke University and North Carolina State University analyzed the effectiveness of a variety of household filters at removing PFAS from tap water.
About one percent of the water pumped to Madison homes is used for drinking and cooking. The rest is used for flushing toilets, doing laundry, dishes, outdoor watering and other needs.
Well 15
Madison Water Utility first discovered PFAS in two Madison wells in 2017 while conducting limited testing at wells near landfills and the airport. One of those wells – Well 15 located on East Washington Ave. – was shut down last year amid community concerns about PFAS chemicals found there. Madison Water Utility is currently undertaking a $50,000 feasibility study looking at possible PFAS treatment at Well 15 and other options. The utility believes the chemicals detected in that well likely migrated from Truax Air Field, about a mile away. It’s unclear where PFAS chemicals found in other city wells are coming from.
Learn more about PFAS chemicals at well 15.
PFAS information from Public Health Madison and Dane County
High concentrations of certain types of PFAS chemicals have been showen to affect health.
View more information on Public Health Madison and Dane County website.
Test results from 2019
View 2019 PFAS testing results here.