WSR 25-20-085

PROPOSED RULES

STATE BOARD OF HEALTH

[Filed September 30, 2025, 10:00 a.m.]

Original Notice.

Preproposal statement of inquiry was filed as WSR 24-20-093.

Title of Rule and Other Identifying Information: Per- and polyfluoroalkyl substances (PFAS); state action levels, state maximum contaminant levels, and public notifications for Group A public water supplies in chapter 246-290 WAC.

The state board of health (board) is proposing amendments to WAC 246-290-315 State action levels (SALs) and state minimum contaminant levels (MCLs) and 246-290-71006 Public notice for contaminants with a SAL and other unregulated contaminants, to align with the federal Environmental Protection Agency's (EPA) new federal standards for PFAS. The board adopted an emergency rule, WSR 25-13-104 on June 18, 2025, to amend WAC 246-290-315 to keep state protections for drinking water in place until EPA's new federal standards take effect. The board adopted subsequent emergency rules while this rule making is ongoing in WSR 24-21-138, 25-05-095, and 25-23-104. The board is proposing permanent rule amendments to incorporate the changes from the emergency rule making to keep current state protections in place until the federal provisions take effect and to change the SALs to align with the new EPA standards before the federal effective date. The board is also considering editorial changes and updates to definitions to assure consistency of terms between federal and state rules in WAC 246-290-010 and 246-290-025.

Hearing Location(s): On November 19, 2025, 3:00 p.m., Washington State Department of Health, 111 Israel Road S.E., Tumwater, WA 98501, Town Center Two (TC2, Rooms 166 and 167); or via Zoom at https://us02web.zoom.us/webinar/register/WN_DlI0Jo2yQUe1KBgX_fIccw.

Date of Intended Adoption: November 19, 2025.

Submit Written Comments to: Shay Bauman, P.O. Box 47990, Olympia, WA 98504-7790, email drinkingwater@sboh.wa.gov, https://fortress.wa.gov/doh/policyreview/, beginning the date and time of filing, by October 27, 2025.

Purpose of the Proposal and Its Anticipated Effects, Including Any Changes in Existing Rules: The purpose of this rule proposal is to incorporate changes from the previous emergency rule makings to keep current state protections in place until the federal provisions take effect and to change SALs to align with the new EPA standards before the federal effective date. The rules are necessary to keep current protections related to SALs in place until the federal effective date, and not the adoption date. This is because many important federal provisions, including public notification of high contaminant levels, are not effective until 2029. The way the state rule was written, the protections that were in place under state SALs would go away until that date. The board is proposing to adopt the stricter contaminant values as SALs so that these customers can receive notifications sooner than the federal effective date to maintain and enhance vital public health protections for drinking water safety.

The board, in collaboration with the department of health (department), is aligning the PFAS testing and reporting requirements in WAC 246-290-315 and 246-290-71006 with the new federal regulation. Because EPA evaluated the most current scientific data to develop PFAS MCLs, these represent the best approach for health protective standards. The PFAS SAL values will be updated to EPA MCL values to provide optimal protection from PFAS in the state's public drinking water. The proposed changes will also maintain state efforts to ensure Group A systems continue state required testing for PFAS, make reporting requirements clearer and ease confusion about which set of health-based standards apply until the federal regulation becomes effective in April 2029.

Reasons Supporting Proposal: To ensure safe drinking water, water must be tested for contaminants. The board establishes SALs and MCLs to ensure contaminate levels are tested and actions are taken above a certain threshold. The board sets criteria for the adoption of SALs and MCLs in WAC 246-290-315, and includes criteria that would apply upon federal adoption of MCLs. WAC 246-290-315(8) states that upon federal adoption of an MCL, the MCL will supersede a SAL and associated requirements, including monitoring and public notice. The emergency rule amended this language to state that when a federal MCL takes effect, the MCL will supersede a SAL and associated requirements, including monitoring and public notice. It is necessary to permanently adopt this language.

The federal government recently adopted MCLs related to PFAS. The MCLs are stricter than Washington's current SALs, but do not take effect until 2029. This means that people served by water systems that detect contamination levels above the MCL, but below the SAL, will not be notified within 30 days that their water contains elevated levels of PFAS. Because Washington already has a notification system in place for the SALs, the board is proposing to adopt the stricter contaminant values as SALs so that these customers can receive notifications sooner than the federal effective date.

Statutory Authority for Adoption: RCW 43.20.050 (2)(a).

Statute Being Implemented: RCW 43.20.050 (2)(a).

Rule is not necessitated by federal law, federal or state court decision.

Name of Proponent: State board of health, governmental.

Name of Agency Personnel Responsible for Drafting: Shay Bauman, 101 Israel Road S.E., Tumwater, WA 98501, 564-669-8929; Implementation and Enforcement: Mike Means, 111 Israel Road S.E., Tumwater, WA 98501, 360-236-3178.

A school district fiscal impact statement is not required under RCW 28A.305.135.

A cost-benefit analysis is required under RCW 34.05.328. A preliminary cost-benefit analysis may be obtained by contacting Shay Bauman, P.O. Box 47990, Olympia, WA 98504-7790, phone 564-669-8929, fax 360-236-4088, TTY 711, email shay.bauman@sboh.wa.gov.

Scope of exemption for rule proposal from Regulatory Fairness Act requirements:

Is not exempt.

The proposed rule does impose more-than-minor costs on businesses.

The following is a brief description of the proposed rule, including the current situation/rule, followed by the history of the issue and why the proposed rule is needed. A description of the probable compliance requirements and the kinds of professional services that a small business is likely to need in order to comply with the proposed rule: The board, in collaboration with the department, is proposing amending drinking water testing and reporting requirements. Amendments will align the state PFAS testing and reporting requirements in WAC 246-290-315 and 246-290-71006 with new federal regulations established in April 2024. Rule changes include updating the contaminant type classifications and updating the method of exceedance detection.

More than 6.2 million1 Washington residents get their drinking water from Group A public water systems (Group A water systems). In Washington state, the board regulates Group A water systems under RCW 43.20.050.

Under RCW 70A.125.080, the department is directed to administer a Group A drinking water program with at least the elements necessary to assume primary enforcement responsibility of the federal Safe Drinking Water Act (SDWA).

The department administers the Group A drinking water program and regulates Group A water systems through a formal agreement with EPA known as "primacy."

The department and the board work closely on rule making for drinking water. The department provides expertise and resources for implementation, and makes recommendations to the board; and the board has the authority to adopt the proposed changes into rule.

In 2017, the board accepted a petition for rule making to set drinking water standards for PFAS in chapter 246-290 WAC. PFAS are chemicals that have been used in industry and consumer products such as carpeting, apparel, upholstery, food paper wrappings, fire-fighting foams, and metal plating worldwide since the 1950s.

PFAS are odorless and tasteless, therefore, contaminant levels can only be assessed through water sampling and analytical testing. Recent studies2 have linked PFAS exposure to widespread health effects, including reproductive effects such as decreased fertility or increased high blood pressure in pregnant women, developmental effects or delays in children, low birth weight, accelerated puberty, bone variations, behavioral changes, and depressed immune system function, including reduced vaccine response. Initial testing and then testing every three years thereafter across Washington state of Group A systems help the department identify impacted drinking water supplies and notify customers of those systems, as well as other nearby private and Group B wells that they may want to test3. This testing protocol starts the process of finding and mitigating local sources.

In April 2024, the federal government published the first National Public Drinking Water Regulation (NPDWR) for PFAS. EPA provided all states with six legal MCLs for PFAS in public drinking water. An MCL is the maximum level of a contaminant allowable in a public water supply as defined by SDWA (42 U.S.C. § 300g-1), codified in 40 C.F.R. Part 141, which sets the maximum legally permissible concentration of a contaminant in public water systems. Under the federal regulation, public water systems have five years from April 2024 to come into compliance with NPDWRs for PFAS by testing for PFAS and ensuring all water sources are below the MCLs. Under the federal regulation, beginning in April 2029 systems exceeding a PFAS MCL will be in violation of federal law and must notify the public and take action to reduce PFAS values to levels at or below the MCL.

This change in federal standard directly affects Washington's rules by triggering the provision in WAC 246-290-315(8) under board authority stating that upon federal adoption of an MCL, the federal MCL will supersede a SAL or a less stringent state MCL, and the associated requirement. This proposed rule change addresses the discrepancy between the public notification requirements of the state level SAL compared to the April 2024 NPDWR.

As a result, Washington benefits from current state level health protections whereas the federal standards, though legally binding once effective, delay implementation until 2029. As a result, while states have until April 2029 to become compliant with the new MCLs, the 30 day public notification requirement is not effective. This creates a regulatory gap: If testing conducted before April 2029 identifies PFAS concentrations above the federal MCLs, public water systems would not be obligated under federal law to notify consumers, even though Washington's state action level requirements already mandate notification within 30 days.

The board, in collaboration with the department, is proposing to align PFAS testing and reporting requirements in WAC 246-290-315 and 246-290-71006 with the new federal regulation. Because EPA evaluated the most current scientific data to develop PFAS MCLs, these represent the best approach for health protective standards. The proposed changes update Washington rule to align PFAS SAL values with EPA MCL values to provide optimal protection from PFAS in the state's public drinking water. The proposed changes also maintain state efforts to ensure Group A systems continue state required testing for PFAS, make reporting requirements clearer, and ease confusion about which set of health-based standards apply until the federal regulation becomes effective in April 2029.

SECTION 2:Identification and summary of which businesses are required to comply with the proposed rule using the North American Industry Classification System (NAICS).

SECTION 3:Analysis of probable costs of businesses in the industry to comply to the proposed rule and includes the cost of equipment, supplies, labor, professional services, and administrative costs. The analysis considers if compliance with the proposed rule will cause businesses in the industry to lose sales or revenue: To gather information on the costs and benefits of the proposed rule changes, the board and the department collaborated to draft a cost survey that was distributed to Group A water operators (Group A water systems, investor owned utilities, and satellite management agencies in Washington state. This survey was distributed via email which included a SurveyMonkey link. The survey was open from July 28th to August 8th.

The board asked Group A water operators to estimate the anticipated costs of several new requirements in the proposed rule. The respondents represent very small (less than 100 service connections) to very large (over 100,000 service connections) Group A water systems and represent all parts of Washington state. Table 1 shows the number of Group A water systems that responded (n=25) and the number of service connections served.

The number of respondents that provided cost estimates are identified in the section-by-section analysis below. In cases where treatment was mentioned, the board and department removed responses deemed as outside the scope of the rule. The costs estimated from Group A water systems (n=6) are discussed in the relevant sectional analyses below.

Description: The proposed rule makes changes to subsection (4) to align with the newly adopted federal rules published by EPA for PFAS on April 10, 2024. The proposed rule makes changes in order to align the federal PFAS testing and reporting requirements. Because EPA evaluated the most current scientific data to develop PFAS MCLs, these represent the best approach for health protective standards. If a water system's testing levels exceed the SAL then they must notify their customers, which is further outlined in WAC 246-290-71006. This does not impact all Group A water systems, only those who are at the current SAL and must begin testing to align with EPA's testing requirements. The proposed rule does not change monitoring or treatment requirements.

The proposed rule also makes several changes to Table 9, which lists contaminants with a SAL. It removes perfluorobutane sulfonic acid (PFBS) as an individual contaminant and instead adds a hazard index metric, which is a tool used to assess the potential health risks from multiple PFAS chemicals. The hazard index accounts for PFBS in the water supply. It also adds hexafluoropropylene oxide dimer acid, an additional contaminant for which EPA adopted an MCL. The proposed rule changes the SAL values in Table 9 to the federal MCL values and adds values for HFPO-DA and the hazard index.

The proposed rule also changes the method to establish exceedance of a SAL value from a confirmed detection to a running annual average (RAA). Confirmed detection is when a contaminant is detected in an initial sample and detected again in a follow-up confirmation sample. Confirmed detection is best used for acute contaminants where a single exceedance can pose an immediate health risk. RAA is a method that uses the average of all sample results for the most recent four quarters for a specific contaminant. This change aligns with the regulations adopted by EPA.

Cost(s): The board and department anticipate there will be costs for testing Group A water systems that have PFAS levels above the current SALs. The proposed rule changes the SALs to align with the federal MCLs from 10 ng/L to 4 ng/L for certain contaminants, there will be water systems that now exceed the SAL. Based on this, the department and board anticipate increased testing which increases costs incurred.

The cost6 of sampling tests for PFAS can range from $286.72 to to $694.567 which includes the cost for field blanks to be shipped with a sample when there is a detection. The average cost for a sampling test that does not require a field blank to be shipped with the sample is $344.79.

The tables below show the costs to test for the contaminants listed in the proposed rule subsection (4). It is important to note, multiple survey respondents included the cost of water treatment when listing increased cost for changing the SAL for the contaminants listed. Those costs are outside the scope of this rule making and not included in the costs calculated below, as treatment is not required until the federal rule takes effect in 2029. Costs were cleaned and analyzed using Microsoft Excel. In cases where treatment was mentioned, the department removed responses deemed as outside the scope of the rule.

Description: The proposed rule amends subsection (8) to state that when a federal MCL takes effect, the federal MCL will supersede a SAL or a less stringent state MCL. Under the current rule language, this would occur upon federal adoption of an MCL.

Cost(s): The board and department do not anticipate any additional costs for establishing that when a federal MCL takes effect, it will supersede a SAL or a less stringent MCL.

Description: The proposed rule adds new language, in subsection (9), to clarify that when a state MCL takes effect, it will supersede a SAL.

Cost(s): The board and department do not anticipate any additional costs for a state MCL superseding a SAL when it takes effect as it clarifies language on already established state requirements.

Description: The proposed rule adds new language in subsection (10) to state that when a federal or state MCL takes effect for a contaminant that has a SAL, public water systems that are not subject to the MCL have to continue to comply with the SAL requirements.

Cost(s): The board and department do not anticipate any additional cost for adding new language in subsection (10) as it clarifies that when a federal or state MCL takes effect for a contaminant that has a SAL, public water systems that are not subject to the MCL must continue to comply with the SAL requirements.

Description: This section requires the purveyor to provide public notice to consumers following the detection of contaminants in a water system with a SAL. Eventually, EPA standards will include a 30-day public notification of detections above the MCLs. The proposed rule updates the PFAS contaminants in Table 17 to align with the changes made by EPA and reflected in Table 9 in WAC 246-290-315.

The proposed rule also changes the method to establish exceedance of a SAL value from a confirmed detection to an RAA. Confirmed detection is when a contaminant is detected in an initial sample and detected again in a follow-up confirmation sample. Confirmed detection is best used for acute contaminants where a single exceedance can pose an immediate health risk. RAA is a method that uses the average of all sample results for the most recent four quarters for a specific contaminant. The delivery methods per the proposed amendments ensure every consumer is notified via direct delivery and additional methods reasonably calculated to reach all consumers.

Cost(s): If a Group A water systems falls between 10 ng/L and 4 ng/L, operators will be required by the proposed rule to conduct public notification for customers.

Table 5 shows the estimated costs for quarterly public notification from a previous analysis done in 2021, with estimates adjusted for inflation to 2025.

Group A water systems must continue providing quarterly public notification as long as they continue to exceed a SAL. Although there are fixed costs included (such as developing required messaging) the variable cost of providing notices to all system users results in variable costs by size of system (e.g., larger costs for the larger systems and smaller costs for the smaller systems (based on the number of connections)). Due to the inclusion of fixed costs (that were not separated from the estimate), it is likely that the annual public notification calculated in Table 3 is an overestimate.

SECTION 4: Analysis on if the proposed rule may impose more-than-minor costs for businesses in the industry. Includes a summary of how the costs were calculated: Yes, the costs of the proposed rule (first year costs of compliance range between $1,000 and $5,000) are greater than the minor cost threshold ($3,282.48).

Summary of how the costs were calculated: Costs were analyzed by individual business (Table 6) with one-time costs added to annual costs to produce an estimated first year cost per business, ranging from $1,000 to $5,000.

*NA reflects that the value was left blank by survey respondents.

**First year costs were calculated by adding up on-time costs and annual costs.

When including the cost of annual public notification (ranging from $35 to $230,257), the range for one business to comply with the proposed rule is estimated between $1,035 and $235,257. The upper limit of the range exceeds the minor cost threshold for water supply and irrigation systems of $3,282.48 (Table 1).

SECTION 5: Determination on if the proposed rule may have a disproportionate impact on small businesses as compared to the 10 percent of businesses that are the largest businesses required to comply with the proposed rule: No, the board and department do not anticipate the proposed rule will have a disproportionate impact on small businesses as compared to the 10 percent of businesses that are the largest businesses required to comply with the proposed rule.

Explanation of the determination: The board and department do not anticipate the proposed rule will have a disproportionate impact on small businesses because the correlation to employees and number of connections served is not indicative of a small business as defined in RCW 19.85.020(3), which states a small business "means any business entity, including a sole proprietorship, corporation, partnership, or other legal entity, that is owned and operated independently from all other businesses, and that has fifty or fewer employees."15 Most water systems are not for profit businesses; they are cities, utility districts, and water and sewer districts. For example, Business A in the survey serves over 100 connections but still has less than 50 employees. The risk of disproportionate impact is not on smaller businesses versus larger businesses, but instead the impact lies based on the number of connections and customers served. Those with fewer customers may be impacted more by sampling costs since they are fixed costs, but larger systems may have much larger costs for public notification.

A copy of the statement may be obtained by contacting Shay Bauman, P.O. Box 47990, Olympia, WA 98504-7990, phone 360-236-4110, TTY 711, email shay.bauman@sboh.wa.gov.

September 29, 2025

Michelle A. Davis, MPA

Executive Director

RDS-5531.2

RDS-6483.1