Testing for PFAS and Keeping Tacoma's Drinking Water Safe

Tacoma’s drinking water remains safe and protected from contaminants, including the group of manmade chemicals labeled PFAS (per- and polyfluoroalkyl substances).

PFAS are manufactured for a variety of industrial purposes. If detected in drinking water, PFAS have the potential to raise health concerns.

Proposed National Primary Drinking Water Regulation

On March 14, 2023, the EPA announced proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS.

The proposed PFAS NPDWR does not require any action until it is finalized. EPA anticipates finalizing the regulation by the end of 2023. Tacoma Water is reviewing the proposed regulations and determining next steps.

Release of Updated PFAS Health Advisories

On June 15, 2022, the EPA announced updated lifetime health advisories for four PFAS compounds in drinking water. A lifetime health advisory identifies the level of a contaminant in drinking water that would protect all people from adverse health effects from a lifetime exposure to PFAS in drinking water. The EPA calculates health advisory levels including a margin of safety and to account for sensitive populations. For these reasons, health advisory levels may be set very low.

The new lifetime health advisories include interim levels for PFOA and PFOS, and final levels for PFBS and GenX PFAS compounds. The interim health advisory levels for PFOA (0.004 parts per trillion) and PFOS (0.02 parts per trillion) are several orders of magnitude lower than the previous level set by the EPA and are below the levels that can be detected with current analytical methods. To illustrate, 1 part per trillion is roughly equal to 1 drop in 20 Olympic-sized swimming pools.

Health advisory levels are non-enforceable, non-regulatory levels.

Tacoma Water’s Green River Test Results

Tacoma Water tested all its sources for fourteen different PFAS in 2018 with results to the lowest detection limits available. No PFAS were detected in water from the Green River, which serves all Tacoma Water customers with the vast majority of their drinking water. To the best of our knowledge, there are no sources of PFAS within the protected Green River Watershed.

Tacoma Water’s Groundwater Test Results

In the 2018 sampling, PFAS were detected in some of Tacoma Water’s back-up groundwater supplies. Two wells with PFOS levels near the EPA’s previous health advisory level were removed from service. The levels in the remaining wells are considered low, below the State of Washington’s current action levels; however, the levels are above the new interim health advisory levels for PFOS and PFOA.

Tacoma Water will continue to monitor PFAS levels in all of our sources and track evolving federal and state regulatory guidance to determine our next course of action to ensure our groundwater is safe. Future testing will monitor for additional PFAS compounds.

Where to Get More Information

For more information about PFAS, including the health and safety risks associated with these compounds, visit the Washington State Department of Health or EPA websites.


Is Tacoma Water safe to drink?

Yes, Tacoma’s water meets all federal and state drinking water regulations and is safe to drink.

The vast majority of the water you receive from Tacoma Water is filtered water that comes from the Green River, where no PFAS were detected.

The utility also tested the blended groundwater (which comes from multiple seasonal use wells) supplied to Tacoma Water customers. While PFAS  were detected in the groundwater at levels above the new interim health action levels for PFOS and PFOA, the levels were below the State of Washington’s current action levels.

What are PFAS compounds?

According to the EPA, PFAS are manmade chemicals that have been manufactured in the U.S. since the 1940s, and are used in a variety of products, including non-stick, stain-resistant, water-resistant products available on the mass market. They are found in furniture, carpeting, non-stick cookware, outdoor clothing, food packaging and other common household products. Certain types of firefighting foam contain PFAS.

According to the Washington State Department of Health, PFAS exposure is widespread; it is estimated that PFAS may be found in the blood of 98% of the U.S. population. Although toxicity and safety data are still being developed, some of the PFAS compounds have been linked to health problems and environmental impacts.

The Health Advisory Level was set by EPA to provide a margin of protection based upon a lifetime exposure to PFAS compounds.

PFAS have been detected in many drinking water sources around the country.  In Washington State, PFAS have been detected in and around the City of Issaquah, Joint Base Lewis-McChord, Naval Air Station Whidbey Island, and Fairchild Air Force Base/City of Airway Heights.

What is the source of the PFAS in Tacoma Water's wells?

Tacoma Water, in cooperation with the State Department of Health, continues to investigate potential sources of groundwater contamination. Throughout the country, PFAS contamination has been primarily discovered in areas near fire training facilities, military bases, and airports that historically used PFAS-based firefighting foam.