PFAS in Drinking Water—Group A Public Water System Support

The State Board of Health (SBOH) revised the WAC 246-290 Group A Drinking Water Rules in December 2021, to require public water systems to monitor for select per- and polyfluoroalkyl substances (PFAS) using specific analytical methods. The SBOH rule established state action levels (SALs) for five PFAS contaminants, listed below. EPA published the final PFAS rule on April 26, 2024. We are working to minimize monitoring for water systems required to sample under all rules discussed on this web page. We have currently scheduled initial federal PFAS monitoring along with increased state monitoring so water systems can satisfy requirements efficiently. The timing of the PFAS scheduling on the 2025 WQMS is very important to follow to satisfy the federal requirements.

For over-all information on PFAS, visit the DOH general PFAS Contaminant webpage. Information is also available in our publication below, PFAS Frequently Asked Questions (FAQ), which may be useful for water systems in communicating with their customers.

PFAS FAQ 331-681 (PDF)

State Monitoring Requirements for PFAS

Group-A Community and non-transient non-community (NTNC) water systems are required to monitor for PFAS beginning January 2023 through December 2025. Each water system's Water Quality Monitoring Schedule lists the PFAS monitoring requirement, which began in 2023. For public water systems with PFAS detections, PFAS Monitoring and Follow Up Actions 331-668 (PDF) outlines the monitoring requirements in the revised SBOH rule. All PFAS detections must be included in your Consumer Confidence Report (CCR).

Systems must collect source samples at the entry point to the distribution system, after all treatment but prior to the first distribution connection, and have them analyzed by EPA Method 537.1 or 533 by a lab accredited for PFAS in drinking water in Washington State (331-700, PDF). Also available in Marshallese, Russian, Spanish, Ukrainian, and Vietnamese.

Transient non-community (TNCs) systems may be required to monitor if their source of supply is near a known PFAS contaminated site. We will notify affected TNCs when more information is known. If you’re required by us to sample for PFAS as a TNC system due to associated risk, you are eligible for free-PFAS testing, as explained in our publication, Emerging Contaminants in Small and Disadvantaged Communities Grant Guidelines 331-765 (PDF).

Systems Required to Sample as Part of EPA’s Fifth Round of the Unregulated Contaminant Monitoring Rule

Water systems required to participate in EPA’s fifth round of the Unregulated Contaminant Monitoring Rule (UCMR5) received an email March 14, 2024, on how to submit their UCMR5 data if you want to use it to also meet our State PFAS requirements. UCMR5 labs are not required to report for you - you may need to provide those results to us. Whether reported by the water system or the lab, the results must be on our state reporting forms.

Free PFAS Analysis Offered

We have a free-PFAS sample program for Community and NTNC systems to help water systems meet state and initial federal PFAS requirements. We will schedule samples in 2025 or 2026, in consideration of any existing data so that the combination of results satisfies initial federal PFAS requirements, while also ensuring the source meets State requirements.

For water systems not currently signed up to participate in this free PFAS sampling program, you can still sign up by submitting you information via our online form at Department of Health, Office of Drinking Water PFAS Free Sampling Enrollment Form.

Systems with detections must collect follow-up samples and comply with the rule requirements.

Funding is limited and we may prioritize systems based on risk if volunteers exceed available funding.

State Action Levels

The SALs represent our recommended limit for 5 PFAS in your everyday drinking water. They were set to protect all people, including sensitive groups, from adverse health effects of PFAS chemicals and were based on the best available science at the time.

Specific PFAS Contaminant	State Action Level (parts per trillion)
PFOA	10
PFOS	15
PFNA	9
PFHxS	65
PFBS	345

Exceeding a State Action Level (SAL) for PFAS

Systems with a PFAS sample result that exceeds an SAL should collect a confirmation sample. If the average results of the initial and confirmation samples exceed the SAL, or if the system doesn't collect a confirmation sample, the system must notify its customers of the SAL exceedance event within 30 days of notification of the exceedance. The templates below contain all the required elements for public notification. It is intended for you to edit with details specific to your water system.

Public Notice PFAS Detection 331-683 (Word)

New Federal PFAS Regulation and Impacts to Public Water Systems

Environmental Protection Agency (EPA) released their final PFAS regulation on April 26, 2024. After the release of EPA’s PFAS rule, the SBOH began the process to adopt the federal rule while maintaining our current rule’s public health protections. The intent is to use current health-based information to support water system operators’ efforts in providing safe and reliable drinking water. For more information on requirements during the transition, please see our publication PFAS Updates 331-750 (PDF)

The federal PFAS rule requires community and NTNC water systems complete initial monitoring requirements by April 26, 2027. The initial monitoring requirements are based upon system size and source water type as shown in the table below. Groundwater systems with populations less than 10,000 must collect two samples that are within five to seven months apart. Groundwater systems serving greater than 10,000 people, all surface water systems and all groundwater under the influence systems must collect four quarterly samples within two to four months apart.

All PWSs serving more than 10,000 people, no matter the source type.	Surface water sources for systems serving less than 10,000 people	All groundwater sources for systems serving less than 10,000 people
Collect four quarterly samples within a 12-month period. Samples must be collected 2 to 4 months apart	Collect four quarterly samples within a 12-month period. Samples must be collected 2 to 4 months apart.	Collect two samples within a 12-month period. Samples must be collected 5 to 7 months apart.

All PWSs serving more than 10,000 people, no matter the source type.

Surface water sources for systems serving less than 10,000 people

All groundwater sources for systems serving less than 10,000 people

Collect four quarterly samples within a 12-month period.

Samples must be collected 2 to 4 months apart

Collect four quarterly samples within a 12-month period.

Samples must be collected 2 to 4 months apart.

Collect two samples within a 12-month period.

Samples must be collected 5 to 7 months apart.

Systems may use previously collected data to satisfy some or all of the initial monitoring requirements. This includes data collected to satisfy our state rule or UCMR 5. When you can use prior results to meet the initial monitoring requirements, the seasonal variation for samples is considered without regard to the year.

PFAS MCLs and Trigger Levels

Initial monitoring results are used to determine compliance monitoring that starts on April 27, 2027. If any source has any sample with a result that has a regulated PFAS with a detection equal to or greater than any EPA trigger level or a non-detect result that are not less the trigger levels, then those sources will begin with quarterly compliance monitoring. For sources with all initial monitoring results less than the EPA trigger levels, they may be eligible for monitoring at a reduced schedule of one sample every three years.

PFAS Chemical	MCL (ng/L or ppt)	Trigger Level (ng/L or ppt)
PFOA	4.0	2.0
PFOS	4.0	2.0
PFHxS	10	5
HFPO-DA (also called GenX)	10	5
PFNA	10	5
PFBS	2,000 (hazard-based water concentration)
Hazard Index (based on PFHxS, HFPO-DA, PFNA and PFBS calculation)	0.5 (unitless ratio)	1 (unitless ratio)

EPA released several quick reference guides and a significant figure fact sheet for the PFAS rule that you may find helpful.

Control of PFAS Overview: A Quick Reference Guide (PDF)

PFAS Initial Monitoring: A Quick Reference Guide (PDF)

PFAS Hazard Index: A Quick Reference Guide (PDF)

PFAS National Primary Drinking Water Regulation Significant Figures and Rounding Requirements (PDF)

Federal rules will require community and NTNC public water systems to mitigate PFAS to ensure all results are below the new MCLs by 2029. Any water system serving water with a running annual average above the MCL by the April 26, 2029, effective date will be required to provide public notification for MCL violations. If you have questions regarding PFAS mitigation, please contact your ODW regional engineer.

PFAS Results in your Consumer Confidence Report

Community water systems that have any detected level of PFAS in the water supply must report the PFAS results on their consumer confidence report, as required in the Washington Administrative Code. All PFAS detections must be included in your data table. We recommend water systems inform customers of their results compared to the MCLs for transparency, but you must include the SALs at a minimum until 2027 when you must present the data compared to the MCLs.

We recommend water systems with non-detect results tell their customers about these samples in a paragraph that celebrates your work and non-detect results.

Mapping PFAS Data: Water System PFAS Results on the PFAS Dashboard

We share all required PFAS results on our PFAS dashboard. Public water systems must test all active, permanent and seasonal sources of their water supply.

Test results are shown as a map or in the data table below the map. Click on each dot to see more information about the water system and source. The dashboard also has PFAS testing statistics.

Funding for PFAS Mitigation

The federal Bipartisan Infrastructure Law makes additional funding available in grants and loans to public water systems for PFAS treatment, new source, or another preferred option for mitigating PFAS contamination. If interested, email or dwsrf@doh.wa.gov or contact the regional engineer for your county. Visit our Drinking Water State Revolving Fund webpage to learn more about funding options.

The Source Water Protection (SWP) grant program provides financial assistance to support drinking water protection projects that reduce the risk of contamination within a source water protection area. If interested, contact chelsea.cannard@doh.wa.gov or the regional engineer for your county. Visit our SWP Local Assistance Grant Program webpage to learn more about funding options.