Pasco, WA Landscaping Rules: Rainwater Harvesting (2026)

Pasco does not publish a city ordinance banning or specially permitting rainwater harvesting, so the controlling rules are at the state level. Washington's Department of Ecology adopted a rainwater interpretive policy in 2009 establishing that the on-site storage and beneficial use of rooftop-collected (or guzzler-collected) rainwater is not subject to the water-right permitting process of Chapter 90.03 RCW. In practical terms, a Pasco homeowner can collect rain from an existing roof and use it on the same property for outdoor purposes such as watering a garden or landscaping without obtaining a water right. To qualify as rooftop-collected rainwater, the roof must be part of a fixed structure above the ground whose primary purpose is something other than collecting rainwater. Two caveats apply statewide: using harvested rainwater as a potable (drinking) supply is more restricted and varies by county, and Ecology reserves the ability to impose local restrictions if rooftop systems are found likely to affect instream flows or existing water rights. Anyone installing larger cisterns, pumps, or plumbing connections should still meet applicable building and plumbing code requirements. Because Pasco also offers low-cost non-potable irrigation water, rain barrels are typically a supplement rather than a primary irrigation source here.