What are PFAS? 

You may have heard about PFAS, but what exactly are they? PFAS stands for per-and poly-fluoroalkyl substances, which are manufactured chemicals that have been used in various industrial and commercial household products since the 1940s. Resistant to heat, oil, stains, and water, PFAS are used frequently because of their unique properties. They can be found in carpeting, cookware, clothing, paint, and firefighting foams, to name a few. They can also be present in our water, soil, air, and foods. For water, they are transported through rainwater run-off and enter surface water (lakes, ponds, etc.) or seep through the soil and migrate into groundwater.


According to the EPA, current scientific research suggests that exposure to high levels of certain PFAS may lead to adverse health outcomes. One concern of PFAS is that many break down very slowly and can build up over time. 

Several PFAS are made up of long chains of carbon-fluorine bonds, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Most uses of PFOA and PFOS were voluntarily phased out by U.S. manufacturers in the mid-2000s but can still be present in the environment due to their persistence and newer PFAS break down into PFOA and PFOS. 

Additional information on PFAS, PFOA, and PFOS can be found here:

Prior Testing

In March 2020, the City collected a voluntary drinking water sample. The PFOA and PFOS levels were measured below the health advisory at that time.  These results, as well as all voluntary samples collected at other Colorado utilities, fire districts, and surface water areas, can be found here:

Current Standards

In June 2022, the EPA announced new drinking water health advisories for PFAS compounds - GenX and PFBS and lowered levels for PFOS and PFOA. Currently, PFOS is set at 0.02 parts per trillion (or 0.02 ppt), and PFOA is 0.004 parts per trillion (or 0.004 ppt). To put that in perspective, 4 grams of PFOA in one trillion liters of water is less than a tablespoon of ground coffee in 400,000 Olympic-sized swimming pools. GenX chemicals are set at 10 ppt and PFBS at 2,000 ppt. 

Additional information from the EPA about the new PFAS compounds health advisories can be found here:

In response to the EPA’s new guidelines, the City of Lafayette chose to voluntarily sample its drinking water system during the summer of 2022. Samples were collected from Baseline Reservoir, Goose Haven Reservoir, untreated water from a pipeline entering the treatment plant, treated water from the Clearwell, and a water storage tank.  Testing was inconclusive due to issues with the testing facility, and samples are being retested.

If you have any questions, please contact Scott Pavlik, Water Treatment Manager, at