PFAS
Frequently Asked Questions
What are PFAS?
Polyfluoroalkyl substances, or PFAS, are a diverse group of compounds resistant to heat, water, and oil. For decades, they have been used in hundreds of industrial applications and consumer products such as carpeting, clothing, upholstery, food paper wrappings, fire-fighting foams and metal plating.
What might be the source of the PFAS (PFOS and PFOA) in DuPont’s drinking water?
The primary source of PFAS in our ground water is widely accepted to be from Firefighting foam from JBLM and been detected in their own wells as well as the City’s.
Learn more about PFAS from the DOH.
What if I have health concerns?
If you are concerned about potential health effects from exposure to PFAS, contact your doctor or health care professional.
See the informational video from the Center for Disease Control (CDC) that discusses safety concerns for human exposure to PFAS/PFOS at the bottom of this page.
Where does my drinking water come from?
Your drinking water comes from deep groundwater through 5 deep water wells that pipe water to two large storage reservoir and is then distributed to your home.
The City started a test pilot program to design a treatment system to remove PFAS. Part of this program includes regular sampling of your drinking water at wells and what is referred to as “entry points to distribution" (EPTD) which is the point where water leaves storage prior reaching customer. The tables below represent a years work of the most recent sample results.
What levels of PFOS and PFOA are safe for humans?
In 2022 the Washington State Board of Health implemented standards that have been adopted by the Washington State Department of Health (DOH) referred to as State Action Levels (SALS). The SALS are intended to establish standards for drinking water purveyors to routinely sample for PFAS and to take certain actions if PFAS levels are found to exceed the SAL.
The DOH Measures PFAS in parts per trillion (ppt). 1ppt is equivalent to one grain of sugar in an Olympic size swimming pool. The DOH adopted SALs for PFOS at 15ppt and PFOA at 10ppt. PFAS are not currently regulated, meaning there isn’t a rule that requires treatment if readings are above a particular level, but DOH and EPA are considering implementing regulations that would require treatment.
The City of DuPont is being proactive in protecting water quality for our customers and is not waiting for a rule to be implemented.
The City was participating with Joint Base Lewis McChord for testing at the Hoffman Hill Wells in December 2018. The 200-foot testing tube has been replaced will all metal piping. Initial results were inconclusive as the Quality Control Sample that was supposed to be clean, showed detection. The City began testing in April, June, August, and October of 2019 to create background test data, and continues to test periodically.
To ensure a safe and reliable water supply, the City is proactively designing for planned construction of new treatment systems that will safely filter out PFAS. The new treatment system uses Granular Activated Carbon (GAC) as the filter media. This is very similar to in-line faucet filters like Brita.
The first step was a Pilot Study. The pilot study work started in June 2020. Granular Activated Carbon (GAC) is a proven treatment method for filtering out PFAS chemicals. The City had contracted with Calgon Carbon for the pilot study. Calgon Carbon is also one of the vendors that will supply GAC material.
The second step, design of the new treatment plant is taking place in 2022. The design has been done with approval of DOH. The full design will produce construction drawings based on the pilot study parameter results. Additionally, the design will develop new water lines to the GAC vessel platform and then waterlines back to the water reservoir.
The final step is construction in 2023. The initial estimated cost is 6 million dollars for both water facility sites.