Frequently Asked Questions about PFAS
Madison Water Utility has received many questions related to low levels of PFAS chemicals detected in water at Well 15 and several other wells. MWU is temporarily relying on other well facilities to serve the Well 15 area on the city’s east side as it waits for a recommended PFAS standard from the Wisconsin Department of Health Services. The recommendation is expected this spring or summer.
According to Public Health Madison Dane County, current levels of PFAS detected in Well 15 are not a threat to health. PHMDC information page on PFAS
What are PFAS?
PFAS are a widespread class of more than 3,000 chemicals used in food packaging, water-resistant clothing, firefighting foams, stain resistant upholstery and carpeting, and nonstick cookware. Low or trace levels of PFAS have been detected at several city wells. While it’s not unusual for man-made chemicals to be detected at very low levels in city water, Madison Water Utility is monitoring PFAS levels to ensure they aren't increasing substantially.
Is my water safe to drink?
Given that PFAS levels in Well 15 have been detected are well below the EPA Lifetime Health Advisory level and haven’t varied much since monitoring began, the water is not considered a potential threat to health. Public Health Madison Dane County does not recommend that residents invest in filtration systems or use bottled water at this time. The same can be said of the five other wells where trace levels of PFAS have been detected.
This guidance also applies to households that include pregnant women, infants and children, and the elderly since the EPA advisory considers these more sensitive populations when it is formulated.
(Information provided by Public Health Madison Dane County's Director of Environmental Health and Environmental Epidemiologist)
Does Well 15 serve my home?
Click to see the Well 15 (East Washington Ave.) service area map:
You can also enter your address to see which of Madison's 23 wells serve your home.
The information is meant to be an estimation of the service areas of the wells, averaging a range of operational conditions over the course of a year. Service areas for any well can change based on season, weather conditions (i.e. drought, heavy rainfall), loss of service at nearby wells, or other unforeseen changes in system operation
Where are the PFAS chemicals coming from?
Madison Water Utility believes the low levels of PFAS chemicals detected at Well 15 (on East Washington Ave.) have likely traveled in groundwater over several decades from Truax Air Field, where firefighting foams have been used. PFAS chemicals have been found in higher concentrations in groundwater at the base.
Unfortunately, cleaning up known contamination at Truax Air Field will not decrease PFAS detections at Well 15 for years or perhaps decades. It takes 35 to 50 years for PFAS to travel in groundwater from the air base to the well. We believe the chemicals we're seeing in the well now were used at the air base several decades ago.
The sources of PFAS at other city wells are currently unknown.
How much PFAS has been found in Madison water?
Madison Water Utility has received test results after sampling in March for PFAS compounds at 14 of the city’s 23 municipal wells. Remaining wells will be tested in the coming months.
Results show that trace levels of PFAS compounds have been detected at four additional wells located on both the east and west sides of the city. That brings the total number of wells with detections of PFAS to six (see map pdf ). PFAS compounds were not detected at the other seven wells tested last month.
The following wells show PFAS detections:
- Well 6 on University Ave. showed detections of a handful of PFAS compounds at levels too low to accurately measure. The EPA has established a Lifetime Health Advisory Level for two types of PFAS (PFOA and PFOS) of 70 parts per trillion (ppt). PFOS was not detected in Well 6. PFOA was found at an estimated level of 0.8 ppt.
- Well 9 on Spaanem Ave. had detections of PFOA and PFOS at an estimated level of 0.8 ppt, as well as trace levels of a mixture of other types of PFAS compounds, most of which are again at levels too low accurately measure.
- Well 14 on University Ave. had trace detections of a mixture of PFAS compounds. Combined PFOA and PFOS concentrations are estimated to be 2.4 ppt.
- Well 11 on Dempsey Rd. had preliminary results that indicate the presence of very low levels of PFAS. However, the lab flagged those results due to its own quality control issues, so the well will be re-sampled in the coming weeks.
- Well 15 on East Washington Ave. was re-tested shortly before it was taken offline in March. Results show PFAS levels at the well are stable, neither increasing nor decreasing significantly. The combined concentration of PFOA and PFOS remain between 11 and 12 ppt.
- Well 16 on Mineral Point Rd. was also re-tested. Results show detections of a mixture of PFAS compounds, most at concentrations too low to accurately measure. In previous testing, no PFOA or PFOS was detected at the well. In this round of tests, the two chemicals were detected at an estimated concentration of 2.5 ppt.
Is there a home filter that can be used to reduce the level of PFAS in drinking water?
Public Health Madison Dane County does not recommend that people who get water from Well 15 invest in filters or bottled water at this time. The water is not considered a potential threat to health and is safe to drink.
However, people searching for peace of mind may be interested in the following information about filtration.
The Minnesota Pollution Control Agency and Minnesota Department of Health tested a small, in-home granular activated carbon (GAC) filter for PFAS removal. You can view the results here.
The agencies report that this type of filter was effective at removing PFC or PFAS from drinking water. A filter certified to meet ANSI/NSF P473 will reduce PFOA & PFOS down to the EPA Lifetime Health Advisory Level of 70 parts-per-trillion. However, detections of PFOA & PFOS at Well 15 are 11 parts-per-trillion, already significantly lower than the health advisory level.
As the Minnesota study showed, any filter will lose its effectiveness over time so it is important to install and maintain filters according to the manufacturer instructions. While not specifically rated and/or certified for PFAS removal, some types of activated carbon (charcoal) and reverse osmosis filters might also reduce PFAS levels in water.
The Michigan Department of Environmental Quality has put together a fact sheet detailing in-home PFAS filtration methods.
Can Madison Water Utility take action to ensure there are no longer PFAS chemicals in our water?
Madison Water Utility is calling for the Wisconsin Air National Guard to clean up known contamination at Truax Air Field. Unfortunately, cleaning up contamination at Truax will not decrease PFAS detections at Well 15 for years or perhaps decades. It takes 35 to 50 years for PFAS to travel in groundwater from the air base to the well. We believe the chemicals we're seeing in the well now were used at the air base several decades ago.
If levels detected at Well 15 begin to increase dramatically, it would be possible to construct a treatment system to remove PFAS from the well's water. Activated carbon could remove PFAS from Well 15, which already has an air stripper to remove volatile organic compounds (VOC). However, the building footprint may need to be enlarged, and there is no space available on our property for expansion.
Any wellhead treatment at Well 15 or Well 16 would cost several million dollars and would take a minimum of two years to design and construct. However, we are investigating those options should PFAS levels rise significantly
The only way for Madison Water Utility to immediately ensure there are no longer PFAS chemicals in city water would be to shut down Well 15 on the east side and Well 16 on the west side (where trace amounts of PFAS may be coming from a nearby landfill). This would impact supply in large parts of the city, particularly during the summer months or if another well were to have a mechanical issue.
A shut down of Well 15 would likely mean more reliance on Well 8 and Well 23, both of which are used sparingly due to high levels of naturally-occurring iron and manganese
The loss of Well 16 would result in mandatory limits on water use from May to September and could limit fire protection capacity on the far west side.
Will Wisconsin set its own drinking water standard for PFAS?
We expect the Wisconsin Department of Health Services to recommend standard for PFAS to the Department of Natural Resources sometime this spring or summer.
Nine other states are setting their own standards for PFAS in drinking water. How do PFAS regulations in other states compare with levels found in Madison?
Well 15 levels are currently lower than regulatory levels set in Minnesota, New Jersey, California, Connecticut, Maine, Massachusetts, New Hampshire and North Carolina. They are not lower than the standard set in Vermont. Click here to see PFAS guidance set in other states and look at how levels at Well 15 compare.
We expect the Wisconsin Department of Health Services to recommend a standard for PFAS to the Department of Natural Resources sometime this spring or summer.
Can Well 15 be shut down?
Yes. It is possible to shut down Well 15 and use other wells to supply water to the area. The well is currently offline as the utility awaits a groundwater standard recommendation from the Department of Health Services. The recommendation should come sometime this spring or summer.
Shutting down Well 15 permanently would reduce the overall reliability of the water supply system on the east and north sides of Madison during summer months (the area east of the Yahara River, from the northern city limits to Buckeye Rd). In 2018, Well 15 pumped 370 million gallons of water into the system. Less than one percent of the water pumped is consumed. The rest is used for fire protection capacity, sanitation, cleaning, irrigation, etc.
A shut down of the well would also likely mean more reliance on Well 8 and Well 23, both of which are used sparingly due to high levels of naturally-occurring iron and manganese
Madison Water Utility looks to Public Health Madison Dane County, the DNR, and Wisconsin Division of Public Health for guidance on this and other issues. None of those agencies has suggested that we should consider shutting down Well 15 due to the levels of PFAS detected in its water. A decision to shut down Well 15 would also end Madison Water Utility’s testing program for PFAS at the well.
Will the WI Air National Guard / Dept. of Defense pay for PFAS removal at Well 15?
National Guard officials have informed us that they will not fund PFAS removal at Well 15 unless levels at the well rise above the EPA's Lifetime Health Advisory Level of 70 parts-per-trillion for PFOA & PFOS. Current levels of PFOA & PFOS at the well are 11 parts- per-trillion.