Per- and Polyfluoroalkyl Substances (PFAS)

What are PFAS?

Per-and Polyfluoroalkyl Substances (PFAS) are a group of manmade chemicals that have been manufactured in a variety of industries around the globe. Exposure to levels of PFAS above health advisory guidelines has been linked to health problems including liver damage, thyroid disease, decreased fertility, lower birth weight, asthma, high blood pressure, and cancer. Some PFAS persist in the environment, and people can be exposed to these chemicals through air, indoor dust, food, drinking water, and various consumer products.

Learn more about PFAS:

Identifying PFAS in Groundwater in Adams County

In 2021, Tri-County Health Department and the Colorado Department of Public Health and Environment launched a project to identify whether there could be PFAS contamination in the groundwater of 11 designated areas by collecting and analyzing PFAS samples from private wells. The goal was to test private wells in selected neighborhoods to learn if PFAS were in the groundwater. In total, 10 private wells were sampled and thirty-one different types of PFAS were tested for in each sample.

Additional details about the 2021 PFAS sampling project in Adams County can be found in the final report

What are the potential health effects from PFAS exposure?

Potential health impacts

We don’t know whether PFAS will cause a specific health impact for an individual. That’s because many factors, such as health history and lifestyle, can cause health impacts.

Children ages 0-5 years, and people who are pregnant, planning to become pregnant, or breastfeeding are more susceptible to health impacts from these chemicals. Other vulnerable populations include people who live in highly contaminated communities and people who have occupational exposure. 


Scientists have the most evidence about the health impacts of two PFAS chemicals: PFOA and PFOS. There is strong evidence that PFOA and PFOS: 

  • Increase cholesterol.
  • Impact the immune system.
  • Decrease infant birth weight.
  • Cause changes in liver function.

There is moderate evidence that PFAS are associated with:

  • Preeclampsia and high blood pressure during pregnancy.
  • Effects on thyroid hormones.

There is also evidence that PFOA increases the risk of kidney and testicular cancer.

Other chemicals in the PFAS family

Scientists also have information about potential health impacts from two PFAS compounds called GenX and PFBS. Most of the information about the health impacts of these two compounds comes from animal studies. Scientists use this information to help us understand how they might impact human health. Not as much is known about the health impacts of other PFAS or mixtures of these chemicals. More research is needed in this area.

  • Based on studies in mice and rats, GenX may be associated with liver damage.
  • Animal studies show that PFBS exposure can result in thyroid, developmental, and kidney effects.
  • Research shows PFBS is less toxic and leaves the human body more quickly than other PFAS. Based on sampling to date, levels of PFBS and GenX in Colorado drinking water are below the health advisories.   

Talking to your health care provider about PFASEn Espaňol

PFAS and your health: pregnancy, infant feeding and young children En Espaňol

How do I know what the PFAS levels are in my drinking water?

If you are on a public water system - you may be able to view your water system’s testing results on the CDPHE webpage . If you do not see your system listed, you can call your public water system directly to ask them if they have tested.

If you are on a private well - you can contact the CDPHE PFAS sampling program to request sampling of your well. They will assess the risk associated with your well and you may be chosen to receive free sampling. You can also contact the Adams County Health Department at 303.288.6816 to explore private well sampling.   

For additional information and to reduce your exposure, please visit the CPDHE website and this resource document for at-home water filters

Updated health advisory and proposed Maximum Contaminant Level (MCL)

On June 15, 2022, the EPA released an updated interim health advisory for PFAS in drinking water that replace those EPA issued in 2016.  These interim health advisories will remain in place until limits are established in a National Primary Drinking Water Regulation (NPDWR). The new advisories are:

  • Interim updated health advisory for PFOA = 0.004 ppt
  • Interim updated health advisory for PFOS = 0.02 ppt
  • Final health advisory for GenX chemicals = 10 ppt
  • Final health advisory for PFBS = 2,000 ppt

These values are much lower than the previous advisory. Adams County Health Department is continuing to follow developments at the state and federal levels including the development of limits in the form of a Maximum Contaminant Level (MCL) by the EPA.  In March of 2023, EPA announced the proposed NPDWR for PFOA, PFOS, PFNA, GenX, PFHxS, and PFBS and is currently under review and awaiting a final rule. Proposed levels are:     


Proposed Maximum Contaminant Level Goal (MCLG)

Proposed MCL (enforceable levels)





4.0 parts per trillion (also expressed as ng/L)




4.0 ppt 

HFPO-DA (Genx)
1.0 (unitless) 
Hazard Index
1.0 (unitless)
Hazard Index

What do these test results mean for my health and do I need to do anything?

Whether or not a person experiences health impacts from exposure to PFAS depends on many factors. Some of these factors include how much PFAS you were exposed to, for how long you were exposed, your medical history and genetics. If you are concerned, please talk to your doctor and learn more about the chemicals. 

Talking to your health care provider about PFASEn Espaňol

If you are concerned about PFAS, you can reduce your exposure by using at-home water filters or using an alternate source of water for drinking and cooking. Look for in-home water filters that have demonstrated that the filter can remove PFAS to non-detectable levels. More information can be found through the link below: 

National Sanitation Foundation (NSF) Certified Filters

You may also look for bottled water that has been treated with reverse osmosis to remove PFAS and states so on its label. Please know bottled water or reverse osmosis systems may not have added benefits that tap water has such as Fluoride. Tap water is significantly less expensive than bottled water and does not result in as much plastic waste as bottled water production. 

Where can I get more information?

Scientists continue to study the health impacts of these chemicals. For the most up to date information about PFAS or if you have more questions about PFAS, please visit If you have additional questions or concerns, contact Adams County Health Department at 303.288.6816.

Content revised 2/21/24


Environmental Health Office

7190 Colorado Blvd.
Ste. 200
Commerce City, CO 80022