Because PFAS is so widely used, the chemicals can get into the water cycle in a number of ways.

Firefighting foam can seep into groundwater supplies. PFAS-containing products in landfills can break down and the chemicals can leach out of the landfill. When PFAS-containing products — such as cookware, cosmetics or water-resistant clothing — are washed with water, trace amounts of the chemicals can be carried down the drain and into the community’s wastewater system.

Because the chemicals are in so many products used every day and don’t break down on their own, surveys by the Centers for Disease Control and Prevention show that most people in the United States have been exposed to some PFAS. Current scientific research suggests exposure to high levels of certain PFAS may lead to adverse health outcomes; more research is underway.

At the same time, a spotlight has been put on the water and wastewater industries to remove these widely used chemicals from our environment, even the trace amounts that may appear in the water system.

The Environmental Protection Agency's regulatory approach to PFAS compounds in drinking water has evolved over the years, including a health advisory in 2016 on two kinds of PFAS (called PFOA and PFOS), and a second, interim health advisory in 2022. Learn more about EPA health advisories.

On April 10, 2024, the EPA finalized the first-ever national standard to limit PFAS in drinking water. The standard covered six PFAS compounds, with limits set for five compounds: PFOA, PFOS, GenX, PFHxS and PFNA. The sixth compound, PFBS, is part a combined limit of four compounds: PFBS, PFNA, PFHxS, PFBS and GenX. Learn more here.

The EPA’s PFAS regulation would require public water systems to: 

• Monitor for six specific PFAS compounds in our drinking water. 
• Notify the public if the levels of the six regulated PFAS compounds are above EPA’s regulatory limits.
• Reduce the levels of these six PFAS compounds in drinking water if test results are above the EPA’s regulatory limits. 

Our experts are evaluating the Environmental Protection Agency’s first-ever regulation on PFAS in drinking water issued April 10, 2024. Our initial review of the EPA’s proposed rule indicated the water Denver Water provides to customers tests well below the limits for the six PFAS compounds included in the agency’s rule.

At the state level, in 2022 Colorado’s Gov. Jared Polis signed a new law (House Bill 1345) that will gradually restrict the sale of PFAS in consumer products, as well as fluids used in the extraction of oil and gas products, starting as early as 2024.

The new state law will prohibit the sale or distribution in Colorado of products that contain PFAS, such as cosmetics, carpets or rugs, fabric treatments, food packaging and juvenile products. Cookware that contains PFAS will have to carry a label.

Denver Water is committed to ensuring a clean, safe water supply for our customers that meets or goes beyond state and federal drinking water standards. Our water quality experts have tested for PFAS-related compounds in the source water that comes into our treatment plants and the drinking water that leaves our treatment plants since 2017. 

Our experts are evaluating the Environmental Protection Agency’s first-ever regulation on PFAS in drinking water issued April 10, 2024. Our initial review of the EPA’s proposed rule indicated the water Denver Water provides to customers tests well below the limits for the six PFAS compounds included in the agency’s rule.

Also, our water quality experts and scientists have been closely studying the evolving information about these chemicals and preparing for solutions in case future test results are above the EPA’s regulatory limits.

We also have been involved in discussions with legislators, state and local regulators and our sister utilities on how to best find, control, remove and prevent PFAS contamination in water.

Denver Water PFAS testing

Our water quality experts have tested for PFAS-related compounds in the source water that comes into our treatment plants and the drinking water that leaves our treatment plants since 2017. Our experts are evaluating the Environmental Protection Agency’s first-ever regulation on PFAS in drinking water issued April 10, 2024. Our initial review of the EPA’s proposed rule indicated the water Denver Water provides to customers tests well below the limits for the six PFAS compounds included in the agency’s rule. The results below are sampling results from 2024.

Current laboratory equipment can reliably detect and quantify compounds down to slightly less than 2 parts per trillion in a sample. Below that level, the tiny trace amounts are so small that test results at these extreme detection limits are only estimations.

The Environmental Protection Agency's regulatory approach to PFAS compounds in drinking water has evolved over the years, including a health advisory in 2016 on two kinds of PFAS (called PFOA and PFOS), and a second, interim health advisory in 2022. Learn more about EPA health advisories.

On April 10, 2024, the EPA finalized the first-ever national standard to limit PFAS in drinking water. The standard covers six PFAS compounds, with limits set for five compounds: PFOA, PFOS, GenX, PFHxS and PFNA. The sixth compound, PFBS, is part of a combined limit of four compounds: PFBS, PFNA, PFHxS, PFBS and GenX. Learn more here.

The EPA’s PFAS regulation would require public water systems to: 

• Monitor for these six PFAS compounds in our drinking water. 
• Notify the public if the levels of the six regulated PFAS compounds are above EPA’s regulatory limits.
• Reduce the levels of these six PFAS compounds in drinking water if test results are above the EPA’s regulatory limits. 

Our experts are evaluating the Environmental Protection Agency’s first-ever regulation on PFAS in drinking water issued April 10, 2024. Our initial review of the EPA’s proposed rule indicated the water Denver Water provides to customers tests well below the limits for the six PFAS compounds included in the agency’s rule

Denver Water will continue testing for PFAS as part of our monitoring protocols. We regularly review our treatment processes and adjust these processes as part of our mission to provide a clean, safe, reliable water supply to our customers.

If PFAS test results go above the EPA’s regulatory limits, Denver Water might be required to add new and potentially costly treatment methods or find alternative sources of water — which isn’t always an available option in the water-starved West.  

Note: The symbol “<” means “less than” and “ppt” means “parts per trillion.”

Denver Water’s PFAS test results* compared to the EPA’s PFAS regulation
PFAS compound	Marston Treatment Plant, treated water 2024	Moffat Treatment Plant, treated water 2024	Foothills Treatment Plant, treated water 2024	EPA’s laboratory detection limits	EPA regulatory limit for drinking water		Does Denver Water exceed the regulatory limit?
GenX	<1.9 ppt	<1.9 ppt	<1.9 ppt	5.0 ppt	10.0 ppt	Weighted combined score** = 1.0	No
PFHxS	<1.9 ppt	<1.9 ppt	<1.9 ppt	3.0 ppt	10.0 ppt
PFNA	<1.9 ppt	<1.9 ppt	<1.9 ppt	4.0 ppt	10.0 ppt
PFBS	<1.9 ppt	<1.9 ppt	<1.9 ppt	3.0 ppt	N/A
PFOA	<1.9 ppt	<1.9 ppt	<1.9 ppt	4.0 ppt	4.0 ppt		No
PFOS	<1.9 ppt	<1.9 ppt	<1.9 ppt	4.0 ppt	4.0 ppt		No

*Test results for 2024.
**The “weighted combined score” is the weighted sum of the test results of four specific PFAS compounds: GenX, PFBS, PFHxS and PFNA. The EPA calls this a Hazard Index and any sum above 1 for a year would be considered a violation of the EPA’s proposed PFAS drinking water regulations. Learn more about the EPA’s proposed PFAS Hazard Index.

Note 1: Denver Water’s 2024 test results in the above chart reflect the detection limits of our laboratory’s capabilities. The EPA’s proposed laboratory detection and reporting limits for PFAS are higher.

Note 2: Denver Water also monitors its water for PFAS-related compounds that are not included in the EPA’s first-ever PFAS regulations issued April 10, 2024, as well as other nonregulated emerging contaminants. 2024 test results of treated water indicated a PFAS compound called PFBA was detected at 2 parts per trillion, which is at the lower limits of laboratory detection and analysis. The EPA’s list of compounds in the agency’s PFAS regulation for drinking water doesn’t include PFBA, although that may change in the future. More information about PFBA is available at the EPA’s website.

You can help! Learn more about where PFAS is used in our society and about alternative, PFAS-free products that you could use instead. This will not only protect your health, but also reduce the amount of PFAS in circulation.

Several groups are working on lists of PFAS-free consumer goods, including PFAS Central.org.