Shoreline, WA Landscaping Rules: Rainwater Harvesting (2026)

The Shoreline Municipal Code treats rainwater catchment as a limited setback encroachment, not a use requiring its own permit. Under SMC § 20.50.040(I)(1)(e)(i), a cistern, rain barrel or catchment system of 600 gallons or less may sit inside a required yard setback if it is less than four feet wide and less than four and one-half feet tall, excluding piping. Larger systems, over 600 gallons, are permitted in a setback only if they cover no more than 10 percent of that required yard, stay at least two and one-half feet from a side or rear lot line, and at least 15 feet from the front lot line; a system placed in a front setback must match the building's architectural style or be screened, as the Director determines.

Cisterns may not block lighting, open space, fire protection or egress access required elsewhere in the Development Code. Enforcement of any setback encroachment that exceeds these limits runs through Planning and Community Development's general code enforcement authority under SMC § 20.30.770, which allows the Director to issue a Class 1 civil infraction or, for willful violations, refer the matter for a misdemeanor charge. Separately, Shoreline's Surface Water Management fee schedule (SMC § FEE.120(B)(4)) gives new or remodeled commercial buildings a 10 percent reduction in their surface water fee for installing a properly sized rainwater harvesting system that uses the available roof surface, citing RCW 35.67.020(3), with the City able to consider a larger reduction depending on how much rainwater is actually harvested.