Yakima, WA Landscaping Rules: Rainwater Harvesting (2026)

Under Washington State Department of Ecology Interpretive Policy Statement POL-1017 (2009), the on-site storage and beneficial use of rooftop or guzzler-collected rainwater is not subject to the water-right permit process of RCW 90.03 — meaning a homeowner or business can install rain barrels or cisterns and use the water on the same property without obtaining a state water right. Collection must be from existing structures with purposes other than collecting rainwater (i.e., roofs), and the water must be used on the property where it is collected. There is no statewide square-foot or volume cap. Locally, the City of Yakima encourages rainwater harvesting through its stormwater utility: owners of new or newly constructed commercial/industrial class buildings that install a properly constructed and maintained rainwater harvesting system are eligible for a 10% credit applied toward that portion of their stormwater charge, on the basis that the system reduces runoff burden on the system and has other water-quality benefits. Residential customers are not subject to the same fee structure but may collect and use rainwater under the same Ecology policy.