Washington Statewide Rule
Washington Allows Rooftop Rainwater Harvesting Without Permit
Key Facts
- Permit needed
- No for rooftop
- Authority
- Ecology Policy 1017
- Plumbing code
- RCW 19.27.031
- Allowed use
- Onsite beneficial use
Summary
Washington law expressly permits rooftop rainwater collection for onsite use without a water right permit, preempting any municipal prohibition on basic harvesting.
(2) The rate a county may charge under this section for stormwater control facilities shall be reduced by a minimum of ten percent for any new or remodeled commercial building that utilizes a permissive rainwater harvesting system. Rainwater harvesting systems shall be properly sized to utilize the available roof surface of the building. The jurisdiction shall consider rate reductions in excess of ten percent dependent upon the amount of rainwater harvested.
Full Breakdown
Under RCW 90.03.260 and Department of Ecology Policy 1017, rooftop rainwater harvesting from existing structures for onsite beneficial use is allowed statewide without applying for a water right. The 2009 policy clarifies that catchment from impervious surfaces such as roofs is exempt from water-right permitting. Cities cannot prohibit residential rooftop collection, although they may impose reasonable plumbing, cross-connection, and building code requirements consistent with the Uniform Plumbing Code adopted under RCW 19.27.031.
Violations & Penalties
Improper plumbing connections may trigger building code enforcement, but no permit is required for typical residential rooftop systems.
Frequently Asked Questions
Do I need a water right to harvest rainwater in Washington?
Can a city prohibit my rain barrel?
Sources
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