South Adams County Water and Sanitation District on Tuesday filed a lawsuit against the city and county of Denver for allegedly contaminating the district’s raw water supply for decades with PFAS-laden firefighting foam runoff from Denver’s firefighting training center.
The suit is another example of the potentially infinite cost of the legacy of “forever chemicals,” as South Adams claims the pollution is “ongoing” and forced the district to build an $80 million water treatment facility for a safe supply.
“There remains a huge deficit” between the cost of that treatment and the state and federal funds South Adams scraped together, and Denver should pay, the district said. South Adams has spent “tens of millions” of dollars handling the PFAS problems since they were discovered in 2018, according to the lawsuit and an interview. District residents are paying higher rates because of the cost of avoiding PFAS, Moreno said.
“Every single day we protect the public’s health by providing clean and reliable drinking water,” district manager Abel Moreno said in an interview Tuesday. “And I’m proud that we do that so well, and it’s disappointing that we’ve had to spend the last seven, almost eight-and-a-half years managing this issue. We really need Denver to be held liable and accountable and own the problem, and come with a solution that remedies the district’s past expenses, and our present expenses, and our future expenses.”
In addition to building the new plant, higher expenses include changing costly filters more frequently to eliminate PFAS and the extra spending on Denver Water for dilution.
A spokesperson for the Denver City Attorney’s Office said Tuesday it had not yet been served with the lawsuit and did not have a comment.
Moreno said the water district has talked with Denver for years about the contamination and possible compensation, but they had come to an impasse, and the time had come to go to court. South Adams remains open to negotiation, he said.
“It would be nice if we didn’t have to end up in court, but we’re fully prepared, which is why we took the action,” Moreno said. “If we can end up anything short of that, that gets the district to where it feels like it needs to be, then I think that just becomes fantastic news for us.”
Municipal water agencies, state governments, private companies and sewage districts across the country are all reckoning with the legacy costs of PFAS chemicals, which have been used in countless consumer products as stain resistance, waterproofing and more. The chemicals do not break down in the environment, and can cause a variety of illnesses ranging from cancers to maternity problems to reduced vaccine response. (PFAS is an abbreviation for perfluoroalkyl and polyfluoroalkyl substances.)
Colorado Attorney General Phil Weiser joined other states in suing PFAS manufacturers like DuPont for the costs of cleaning up water supplies, rivers and other damage.
The South Adams district, anchored by Commerce City, announced in 2022 it would be paying Denver Water $2.75 million that year for enough supply to dilute local well water tainted by PFAS from firefighting foam runoff.
The district serves about 75,000 people, and said at the time it needed a new $130 million treatment plant to filter out PFAS and past contamination from the industrial solvent 1,4-dioxane, in order to avoid buying relatively expensive Denver water indefinitely. Since then, South Adams has nearly completed the new plant at a cost of $80 million, Moreno said, with $60 million coming through the federal law and $17 million in borrowing.
South Adams said in 2022 it had shut off wells near a metro firefighting training facility, Denver’s Roslyn Fire Training Facility at 5440 Roslyn St. The district believed other wells it owns may have been contaminated by firefighting-related runoff from the former Stapleton airport. There has not been any connection established between PFAS in South Adams County water supplies and known PFAS contamination at the nearby Suncor Energy refinery, county officials said.
The lawsuit’s initial filing says South Adams has test results from wells at the fire training facility. It compares those levels with current EPA standards.
“In 2016, under the federal Safe Drinking Water Act, EPA set Health Advisory Levels for PFOA and PFOS (two common variants of the family of chemicals) at 70 parts per trillion, respectively. The Agency then drastically lowered the (levels) in June 2022 to 0.004 ppt and 0.02 ppt, respectively,” the suit notes. Since then, the EPA promulgated a formal national drinking water regulation setting maximum levels for PFOA and PFOS of 4.0 ppt, the suit says.
Meanwhile, the suit says, in November 2025 district wells were measuring as high as 342.6 ppt PFOA and PFOS, combined.
Wells under the Denver facility, the suit adds, showed “PFOS concentrations in groundwater at the northern end of the site exceeded 6,600 ppt, and PFOS concentrations in groundwater near the eastern part of the site exceeded 20,000 ppt. PFOS concentrations in groundwater north and downgradient of the Fire Training Facility ranged as high as 2,870 ppt,” the suit says.
An analysis by environmental and legal advocacy groups in the fall of 2021 said Colorado has more than 21,000 locations likely to have handled PFAS, which encompasses a large number of chemicals that have repellant or lubricant properties. Runoff from airfields and their accompanying firefighting facilities have contributed to contamination in Fountain Creek and nearby communities, among other locations.
A state testing program for local water agencies found more than 100 with contamination or a need for retesting to determine the level of contamination. Some communities applied for federal Bipartisan Infrastructure Law and state grants to pay for new treatment options. The state has also run buyback programs to allow firefighting agencies to swap out PFAS-laden foam with newly developed options without the chemicals.
The new South Adams treatment facility should be operating by the end of this year, officials said.