Translate
PFAS data and test results
As stewards of our region’s water and land, King County shares in the growing concerns around PFAS chemicals and the risks they present to human health and the environment. As we work to address the effects of PFAS on our community and environment, King County is testing the water from our landfills and wastewater treatment facilities, local marine and freshwater fish, and soil around the King County Airport to understand and measure the scope of PFAS contamination in King County.
Our testing, research, and monitoring efforts will help inform proactive measures to address PFAS and other chemicals of concern in our area.
As data and testing results are published, we will provide information on this page.
PFAS in King County Waste Systems
April 2025
Many state and local governments are taking action to better understand levels of local PFAS contamination and hold manufacturers accountable. As King County is taking steps to reduce sources of PFAS, a core part of our response is measuring PFAS levels in our waste streams, as we already routinely do with other contaminants. The data will help us make better informed decisions and determine next steps and actions.
From October 2023 to August 2024, the King County Department of Natural Resources and Parks (DNRP) collected monthly samples of wastewater and biosolids from our three regional wastewater treatment plants and leachate from our Cedar Hills Regional Landfill to test for 40 types of PFAS compounds.
The results from the 12-month study found low levels of PFAS were present in King County’s waste systems likely coming from diffuse sources, namely from the everyday products that people in our service area use and send down drains, toilets, and put in the trash. This makes it essential that King County, regulators, manufacturers, and local communities work together to control upstream sources of PFAS from our consumer waste products in order to reduce PFAS from entering our waste systems and ultimately the environment.
View full report.