PFAS compounds are an emerging water quality concern, and they are not yet regulated under the Safe Drinking Water Act. Here are many of the questions our customers have asked us about PFAS and Madison Water.
What are PFAS?
PFAS are a class of chemicals widely used in cookware, food packaging, stain and water-resistant clothing, upholstery and firefighting foams. The compounds do not degrade and are showing up in dust, soil and water worldwide.
High levels of PFAS exposure have been linked to a variety of health concerns, including increased risk of some types of cancer. So far, PFAS are not regulated under the Safe Drinking Water Act.
Current levels of PFAS detected in Madison wells are far below both the EPA Lifetime Health Advisory Level and the Wisconsin Department of Health Services recommended groundwater standard, both of which are set to protect public health.
According to Public Health Madison Dane County, the levels we're seeing in Madison are not considered a threat to health.
You can enter your address here to see which of Madison's 23 wells serve your home. Many addresses are served by more than one well. 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. (currently shut down) have likely traveled in groundwater over several decades from Truax Air Field, where firefighting foams have been used. PFAS chemicals have been found in high 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 been conducting advanced testing of the city’s 23 water wells looking for PFAS compounds. Most wells with PFAS detections show trace amounts of a mixture of several types of the compounds, many of which are at levels too low to accurately measure.
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 invest in filters or bottled water.
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. Please note the units of this study are in ppb (parts per billion) – we report PFAS levels in ppt (parts per trillion) which is 1,000 times smaller.
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 in Madison wells are 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.
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, the likely source of PFAS found at Well 15 on East Washington Avenue (currently shut down). 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.
It is possible to construct a treatment system to remove PFAS from the well's water. However, the building footprint may need to be enlarged, and there is no space available on our property for expansion.
Any wellhead treatment to remove PFAS would cost several million dollars and would take a minimum of two years to design and construct. However, we are investigating those options.
Because the sources of trace levels of PFAS in other city water is unknown, there is currently no remediation action that can be taken. It's unclear if wellhead treatment could successfully remove the very low levels of PFAS found in these wells. Shutting down all wells containing PFAS would leave large parts of the city with no water.
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 (currently shut down) 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 11-12 parts- per-trillion.