Laws and rules
As we administer laboratory accreditation, we are implementing methods and standards specified in federal and state regulations for environmental and drinking water testing.
Clean Water Act analytical methods — the methods update rules
We adopted the 2021 Clean Water Act (CWA) Methods Update Rule (MUR) on June 30, 2024.
It will remain in effect until we adopt the next MUR — the 2023 MUR that EPA promulgated on April 16, 2024, known as rMUR 2. Before this happens, we will send notice to our accredited labs providing information and instructions.
Drinking water requirements
We administer both federal and state requirements for Accreditation of Laboratories performing Drinking Water Analysis.
State Lab Rule for drinking water
Washington state drinking water requirements are at WAC 246-390, the Department of Health Lab Rule.
The Lab Rule specifies that labs must be able to meet state required detection limits and meet notification requirements for state-regulated contaminants. Notification must be submitted to Washington Department of Health and the public water system within the time frame and circumstances specified in rule. See WAC 246-390 for details.
Recent updates include a Jan.15, 2026, update for PFAS testing. See the fact sheet Group A Public Water Supplies — PFAS Rulemaking from the state Department of Health to learn more.
Safe Drinking Water Act requirements
Relevant sections of 40CFR141 include:
- National Primary Drinking Water Regulations from the Federal Code of Regulations
- Total Coliform Rule
- Groundwater Rule
- Secondary Contaminants
SW846 compendium for solid and chemical wastes
EPA's SW846 site covers methods for testing solid and chemical matrices.
Update VII for Phases I and II
- Phase I — Modernizing Ignitable Liquids Determination
- Phase II — PFAS Methods 3512 and 8327
Contact information
Rebecca Wood
Laboratory Accreditation Unit Supervisor
rebecca.wood@ecy.wa.gov
360-742-7022