On-Site Sewage Systems

Chapter 246-272A WAC, On-Site Sewage Systems, establishes standards for the siting, design, installation, use, care, and management of on-site sewage systems. On March 6, 2018, the Washington State Board of Health (Board) filed a CR-101, Preproposal Statement of Inquiry, WSR 18-06-082, to explore possible updates to the rules.

The Board and the Washington Department of Health (Department) used a collaborative rulemaking approach to gather input during the rulemaking process. The Department’s On-Site Sewage Rule Revision Committee served as the main advisory committee for this rulemaking.

The Board adopted the proposed changes on January 10, 2024. The adopted revisions incorporate recommendations from the Onsite Rule Revision Committee and other issues raised by interested parties. Based on input from interested parties, the On-site Sewage System rule becomes effective with a staggered timeline.

  • Effective April 1, 2024: Changes to WAC 246-272A-0110
  • Effective February 1, 2025: Maintenance Service Provider approval requirement
  • Effective March 1, 2025: All provisions of the rule excluding changes to WAC 246-272A-0110, the maintenance service provider approval requirement, and the property transfer inspection requirement.
  • Effective February 1, 2027: Property transfer inspection requirement.

Key changes to the rule include:

  • Local management plans
  • Field verification of proprietary products
  • Property transfer inspection
  • Remediation
  • Repairs
  • Minimum lot sizes
  • Approval of maintenance service providers

On March 1, 2024, the Board filed the CR-103P, a permanent rulemaking order. The CR-103P, filed as WSR 24-06-046, announces to the public that the proposed rule has been adopted and will become effective.

Below are Code Reviser filings for the permanent rulemaking on chapter 246-272A WAC, On-Site Sewage Systems. This includes WSR 06-12-108, originally filed in 2006 regarding on-site sewage system drainfield remediation technologies and withdrawn as WSR 22-17-112. The issues were addressed in the permanent rulemaking on the chapter.

Supporting documents for permanent rulemaking on chapter 246-272A WAC, On-Site Sewage Systems:

  1. January 10, 2024, Board Meeting Recording
  2. January 10, 2024, Board Meeting Minutes
  3. CR-102 (with SBEIS and proposed rule language)
  4. Proposed rule language
    -Spanish Version
  5. Significant Analysis
  6. Small Business Economic Impact Statement
  7. Summary of rule changes
    - Spanish version
  8. Key rule changes
    Spanish version
  9. Homeowner Cost Impacts at a Glance
    - Spanish version
  10. Concise Explanatory Statement

Before adopting the permanent rule, the Board adopted emergency rules amending WAC 246-272A-0110. The emergency rules allowed retrofits and maintenance of proprietary treatment products with comparable components during supply chain shortages or similar manufacturing disruptions to avoid public health risks associated with poor system performance. 

Emergency rules are effective for 120 days after filing. Identical or substantially similar emergency rules may be adopted in a series if the agency is actively working to adopt the rule as a permanent rule. Below is the order of Code Reviser filings for this emergency rule, including the most recent CR-103E filed as WSR 24-04-071 on February 02, 2024. The issue is being addressed in permanent rulemaking on the chapter. The Department of Health withdrew the most recent Emergency rule, as the issue was addressed in the permanent rulemaking.

For more information on these rulemakings visit the Department’s rulemaking web page and to stay informed on the rulemaking and other wastewater related information, sign up for wastewater email notices from the Department.

Statutory Authority: RCW 43.20.050, RCW 70A.105, RCW 70A.110, RCW 43.20.065
State Board of Health Contact: Shay Bauman, 564-669-8929
Department of Health Contact: 
Peter Beaton, 360-236-4031