PFAS are a family of manufactured chemicals that have been widely used in consumer products since the 1940s. They can be found in water, soil, air, and food, as well as in materials found in our homes or workplaces, from food packaging to personal care products. PFAS are emerging contaminants – meaning that there is a new awareness or understanding about how they affect public health. PFAS, like other emerging contaminants, are the focus of active research and study, which means that new information is released frequently.

The City of Stillwater recently learned that some of its drinking water wells produce water that exceeds MDH’s Health Based Guidance Values (HBVs) and the Maximum Contaminant Levels (MCLs) for PFAS recently established by the Environmental Protection Agency (EPA). Preliminary testing conducted by MDH indicated higher levels of PFAS and was confirmed by follow-up testing. There is no immediate health risk posed by Stillwater’s drinking water at this time.

The City is evaluating short- and long-term solutions to meet the EPA’s MCLs by 2029.The City is working with an engineering firm to evaluate options for PFAS mitigation that the City can consider, as shutting down wells is not a long-term, viable solution.

The City will also be hiring an independent laboratory to take additional samples of water from the City’s water system. The data from this testing, along with the engineering evaluation, will help the City determine the appropriate path forward. To pay for the cost of the engineering evaluation and testing, the City will be using a grant received in the amount of $102,000 from the Minnesota Pollution Control Agency’s (MPCA) Drinking Water Planning and Design Funds for PFAS Treatment. The City is also actively seeking funds from other state and federal programs to assist with anticipated mitigation projects.

Per- and polyfluoroalkyl substances (PFAS) are a family of manmade chemicals that have been widely used in consumer products since the 1940’s. PFAS can be found in water, soil, air, and food as well as materials found in our homes or workplaces including

• Water-repellent clothing, non-stick cookware, paints, sealants, wood stain, and some personal care products.
• Food packaging, including grease resistant paper, microwave popcorn bags, pizza boxes and candy wrappers
• Food, including fish caught from water contaminated by PFAS and dairy products from livestock exposed to PFAS.
• Fire fighting foam in aqueous film-forming foams (AFFFs) used to extinguish flammable liquid-based fires.
• Biosolids – for example fertilizer from wastewater treatment plants that is used on agricultural lands can affect ground and surface water and animals that graze on the land.

Taken from the Environmental Protection Agency: PFAS Explained | US EPA

The Minnesota Department of Health (MDH) uses health-based values to evaluate health risks from individual PFAS substances. Health guidance values are designed to protect the most vulnerable populations for up to a lifetime of exposure. If more than one PFAS is found in drinking water, MDH evaluates their additive health risk using the Health Risk Index.

There is little to no health risk from drinking water with PFAS levels at or below guidance values. Drinking water with a PFAS Health Risk Index under one presents little to no health risk.

Drinking water with PFAS levels above guidance values or the Health Risk Index poses a potential health concern. It does not represent an immediate health risk. The guidance values are based on multiple safety factors and are overprotective for most people.

PFAS are emerging contaminants – meaning that there is a new awareness or understanding about how they affect public health. PFAS, like other emerging contaminants, are the focus of active research and study, which means that new information is released frequently, and the understanding of risks is evolving.

Community water systems with elevated PFAS can take actions to reduce PFAS levels. These systems can lower PFAS levels through treatment or reduced pumping from contaminated wells. For more information, please check out the MDH website: PFAS Testing of Public Water Systems - MN Dept. of Health (state.mn.us)

The City of Stillwater operates 3 different pressure zones. The water is mixed in the system so not any one particular well serves a particular area.

According to MDH, consuming water with PFAS above the health-based guidance values, which are designed to protect the most vulnerable populations for a lifetime exposure, can increase risk of health effects. These increased health effects include:

• Immune suppression such as decreased vaccination response
• Lower birth weights
• Increased risk of kidney and testicular cancer
• Changes to liver function such as higher cholesterol and elevated liver enzymes
• Thyroid disease and dysfunction

• City of Stillwater: Provides water services to residents and businesses within the community.
• Minnesota Health Department (MDH): Responsible for ensuring safe drinking water and enforcement of the Safe Drinking Water Act (SDWA). MDH performs regular testing of community water systems. MDH has developed health-based guidance values to represent levels for several PFAS in drinking water.
• Minnesota Pollution Control Agency (MPCA): Responsible for preventing, managing and the cleanup of PFAS pollution. Grants in aid for PFAS mitigation in community water systems is overseen by MPCA.
• Environmental Protection Agency (EPA): Responsible for the Safe Drinking Water Act (SDWA). The EPA sets national health-based standards to protect against naturally occurring and man-made contaminants that may be found in drinking water. The SDWA defines a contaminant as anything other a molecule of water.

Established by the US EPA and considers the health impact, cost, and technology of prevention and/or treatment. All public water systems must meet MCLs. States are allowed to enforce lower (more strict) standards than MCLs, but are not allowed to enforce higher (less strict) MCLs. 

An HBV is the level of a contaminant that can be present in water and pose little or no health risk to a person drinking that water. HBVs are guidance used to make decisions about managing the health risks of contaminants in groundwater and drinking water. HBVs are updated when significant new information is available. HBVs do not consider the cost and technology of prevention and/or treatment and may be set at levels that are costly, challenging, or impossible for a water system to meet.

To see PFAS testing results in community water systems, visit Interactive Dashboard for PFAS Testing in Drinking Water https://www.health.state.mn.us/communities/environment/water/pfasmap.html

No, the City does not have information about PFAS at the tap. Property owners who are concerned about water quality should refer to information on the MDH website: Home Water Treatment Fact Sheet - MN Dept. of Health (state.mn.us) and on the EPA website: FACT SHEET (epa.gov)

To learn more about testing private wells for PFAS, safe levels in drinking water, health effects, and ongoing activities, visit Per- and Polyfluoroalkyl Substances (PFAS) and Private Wells - MN Dept. of Health (state.mn.us)

MDH has developed a fact sheet and resources for Minnesotans to consider when installing home water treatment systems. You may find information here: Home Water Treatment Fact Sheet - MN Dept. of Health (state.mn.us)

You may contact City Staff by sending an email with your questions and concerns to waterupdates@stillwatermn.gov or calling 651.430.8830