Onsite Nonpotable Water Systems Rulemaking

What's Happening?

We are developing rules to establish risk-based water quality and construction standards for the on-site treatment of nonpotable water. The treated  nonpotable water can then be put to beneficial end uses for things like toilet flushing, irrigation, and dust suppression.

Current work is underway on the required economic analyses. If you have input into costs and benefits of this rulemaking please reach out to Jocelyn Jones at mailto:jocelyn.jones@doh.wa.gov.

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RCW 90.46.290 was enacted in 2021 requiring us, in consultation with the state building code council and the state association of plumbers and pipefitters, to adopt rules to establish risk-based water quality standards for the onsite treatment of nonpotable alternative water sources for nonpotable end uses and construction standards to adopt the risk-based water quality standards.

The purpose of this rulemaking is to implement RCW 90.46.290. These rules will allow for the use of locally issued building permits, rather than waivers, for the onsite treatment of nonpotable alternative water sources for nonpotable end uses. National standards will be considered as a part of this rulemaking.

These rules would apply to multifamily residential, commercial, and mixed-use buildings, and district-scale projects including a mix of multifamily residential, commercial, and mixed-use buildings. Water sources include wastewater from all domestic fixtures, gray water, rooftop runoff, stormwater, foundation drainage, and AC condensate. Water treated to the established risk-based water quality standards may be used for end uses such as toilet and flushing, irrigation, and dust suppression. 

Get Involved!

A Rules Advisory Committee (RAC) comprised of impacted agencies and interested parties, including Department of Ecology, State Building Code Council, Washington State Association of Plumbers and Pipefitters, local health jurisdictions, municipalities, and design consultants has been working to draft rules. Review the draft rule!

Contact Jocelyn Jones, Rules Coordinator, if you would like to participate in the RAC.

RAC Meeting Date Link
October 12, 2021 Presentation Slides
October 18, 2021 Presentation Slides
April 21, 2022 Presentation Slides

Rulemaking Files


What's This?

Date Filed

CR-101 (PDF)

Announces intent of rulemaking

August 9, 2021