Our number one priority is providing safe, reliable, great tasting water to the community. Which is why I am sharing with you what we are doing to monitor for emerging contaminants such as PFAS.

There’s been a lot of media attention lately on PFAS chemicals being detected in drinking water. PFAS is an abbreviation for per- and polyfluoroalkyl substances which are manmade chemicals used in metal plating and a wide variety of consumer products including fire-suppressing foam, carpets, paints, polishes, and waxes. Nationwide PFAS is being detected in source waters near manufacturing plants using PFAS in their processes. Here in Colorado, communities near military bases and airports have been seriously impacted by the presence of PFAS chemicals in their water supplies.

The Roxborough community’s water supply is mountain snow melt diverted from the South Platte River. Roxborough Water and Sanitation District is fortunate to have excellent source water and working relationship with both Denver Water and the City of Aurora which use the same source. Both entities continue to monitor and share their PFAS data with us.

Denver Water samples the South Platte River above Chatfield Reservoir quarterly for Total PFCs and Total PFCs-Narrative Constituents. Throughout 2020-2021 all their samples came back below the detection limit as measured in parts per trillion (or nanograms/liter or ng/L). The City of Aurora (Aurora) provided data for one of their water treatment plants that sources water from Rampart Reservoir, located in the Roxborough area, for 12 different PFAS chemicals, and all but one were below the detection limit, with one chemical (Perfluorohexanoic acid PFHxA) just slightly above the detection limit at 0.48 parts per trillion (or ng/L). There is currently no Lifetime Health Advisory for PFHxA. The “detection limit” is the lowest level a laboratory can consistently analyze. There were no reportable levels of PFAS in the source water.

The U.S. Environmental Protection Agency (EPA) recently released new Final Lifetime Health Advisories for two PFAS chemicals, Hexafluoropropylene oxide dimer acid (GenX) of 10 parts per trillion (ng/L) and Perfluorobutanesulfonic acid (PFBS) of 2,000 parts per trillion (ng/L). Aurora analyzed for both chemicals and results were below detection. The EPA also released Interim Lifetime Health Advisories for Perfluorooctanesulfonic acid (PFOA) of 0.004 parts per trillion (ng/L) and Perfluorooctanesulfonic acid (PFOS) of 0.020 parts per trillion (ng/L). Aurora also sampled for both chemicals and results were below detection. One part per trillion can be visualized by thinking of a single drop of food coloring in 18 million gallons of water or a single second out of 32,000 years.

Continuing to monitor for PFAS, we have signed up to participate in a rigorous sampling program to be implemented by the Water Quality Control Division of the Colorado Department of Public Health and Environment. In early July, contractors working for the state will come out to the District’s Larry D. Moore Water Treatment Plant and sample both the raw water entering the plant and the finished drinking water. We should have the results of that sampling by mid to late-August and will do an updated post to share the results. Beginning in 2023, Roxborough’s water will be sampled for 29 per- and polyfluoroalkyl substances (PFAS) under EPA’s Unregulated Contaminants Monitoring Rules (UCMR 5), and those results will be included in future Water Quality Reports.

While we monitor for emerging contaminants, the water in Roxborough continues to be safe to drink. You can review the current Water Quality Report on this website by clicking here.

Barbara Biggs, General Manager Roxborough Water & Sanitation District Read Barbara Biggs’ BIO