Bellingham, WA Landscaping Rules: Rainwater Harvesting (2026)

Under WA Department of Ecology Interpretive Policy Statement POL-1017 (WSR 09-21-031, 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 in Bellingham may 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 (e.g., roofs), and the water must be used on the property where it is collected; there is no statewide square-foot or volume cap. Bellingham does not impose a separate barrel permit. Rainwater harvesting is actively promoted as a low-impact development (LID) and stormwater-management practice, particularly within the Lake Whatcom watershed under BMC Chapter 15.42 (Stormwater) and BMC Chapter 16.80 (Lake Whatcom Reservoir Regulatory Chapter), because reducing rooftop runoff helps meet the phosphorus TMDL load reduction requirements for the Lake Whatcom reservoir. Larger cisterns or systems tied into building plumbing may trigger Building Department review under standard plumbing code, and any system used for indoor potable use requires WA Department of Health review.