Washington adopting new EPA drinking water regulation

In a website announcement on April 10th, 2024, the Washington State Department of Health (DOH) stated they will be adopting the EPA's new Federal drinking water regulation for PFAS. 

A comparison of Washington State Action Levels (SAL) with the new EPA mandated maximum contaminant levels (MCL) follows:​

Chemical	WA SAL	EPA MCL
PFOA	10 parts per trillion (ppt)	4 ppt
PFOS	15 ppt	4 ppt
PFNA	9 ppt	10 ppt
PFHxS	65 ppt	10 ppt
PFBS	345 ppt	See mix of 2 or more category
HFPO-DA (GenX chemicals)*	N/A	10 ppt
Mix of 2 or more (PFNA, PFHxS, HFPO-DA, PFBS)**	N/A	Hazard Index of 1**

According to information published by the DOH:
* GenX chemicals have not been found in Washington State
​** Hazard Index is a long established approach EPA uses to understand health risk from a mixture of chemicals. The index is made up of a sum or fractions. Each fraction compares the level of each PFAS measured in the water to the health-based water concentration

The DOH has announced that "State SAL's will remain in effect until the Washington State Board of Health adopts the new federal MCLs which can take up to two years."  Like the writing and passage of any law, this will take time for the state to adopt the Federal regulation (which is more stringent in nearly every category) as their own legally binding law in Washington. This law should be in place before the EPA's required mandate to have treatment in place within the prescribed five year limit to treat water to meet MCLs for the stated PFAS chemicals.  

Further, the DOH has stated they will work with public water systems to address treatment, reduction of exposure, and work to leverage any state and federal funding they can. 

It is encouraging that the state of Washington will move beyond simple reporting requirements when PFAS is found in the drinking water, to now  mirror Federal requirements that mandate actual TREATMENT levels. This more restrictive rule will reduce exposure risks from the stated PFAS chemicals in our drinking water and is a step in the right direction for the state of Washington.