WAC 173-50: Accreditation of Environmental Laboratories

On Sept. 1, 2023, Ecology updated  Chapter 173-50 WAC,  Accreditation of Environmental Laboratories. The updated rule will take effect on Oct. 2, 2023.

This rule:

  • Amends wording in existing sections and adds new sections to increase clarity and to incorporate existing best practices, quality control, and rules for participation in the lab accreditation program:
    • Updates and clarifies definitions.
    • Requires laboratories to submit Standard Operating Procedures (SOPs).
    • Updates and clarifies quality control requirements.
    • Adds data-management and record traceability requirements.
    • Requires an additional proficiency testing (PT) sample per parameter per year for microbiology parameters.
    • Clarifies procedural requirements for PT.
    • Clarifies and updates audit procedures and frequency.
    • Clarifies requirements for accreditation of drinking water laboratories.
    • Clarifies that laboratories must notify Ecology at least 30 days prior to a permanent laboratory move.
    • Updates reasons for suspension of accreditation to include: violation of federal law.
  • Amends the fee structure to meet current Ecology Laboratory Accreditation Unit implementation costs and addresses the need to increase fees to cover future cost increases.
  • Clarifies existing rule language and updates references.

Rulemaking timeline


Announcement phase (CR-101)

Filing date:
Oct. 10, 2022

Announcement documents

Rule development phase

Oct. 10, 2022 – April 17, 2023

Public input & involvement

We completed three stakeholder workshops in November and December 2022. Materials from those workshops are available below. 

Meeting documents from stakeholder workshops:

Rule development documents:

Informal public comment period — Nov. 2, 2022, to Jan. 4, 2023

Rule proposal phase (CR-102)

Filing date:
April 18, 2023

Rule proposal documents:

Comment period

Comments were due June 7, 2023.  

We reviewed comments received and plannned for adoption on Aug. 28, 2023. See above for documents related to the Proposal phase of the rulemaking.

You can submit comments through one of the following ways:

  • Read comments
  • Mail written comments via standard US mail to:
    Ryan Zboralski
    Department of Ecology
    PO BOX 488
    Manchester, WA 98353-0488
  • Attend a public hearing — see below.

We held two public hearings via webinar. These were online meetings that you could attend from any computer with internet access. You could also call in at the number below. Each event included a presentation and question-and-answer session, followed by the opportunity to provide testimony. 

May 25, 2023, 9 a.m. – 12 p.m

May 31, 2023. 1 p.m. – 4 p.m.

For audio-only participation, you could register for one of the events above, then call US toll number 253-215-8782. Enter the meeting ID 825 7062 1945 and passcode 174911.

To request ADA accommodations, contact our ADA Coordinator by May 22, 2023, at:
Phone: 360-407-6831 (voice)
TTY: 877-833-6341 or 711 relay service

Additional languages

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To request ADA accommodation for disabilities, or printed materials in a format for the visually impaired, contact Ecology's ADA Coordinator by email at ecyadacoordinator@ecy.wa.gov, or call 360-407-6831. People with impaired hearing may call Washington Relay Service at 711. People with speech disability may call TTY at 877-833-6341.