Sammamish, WA Landscaping Rules: Artificial Turf (2026)

Sammamish permits synthetic/artificial turf and treats it as a landscaped yard area — yard areas may include landscaped areas, uncovered decks less than 18 inches above grade, or artificial turf. The significant regulatory consideration is stormwater. Under the Sammamish addendum to the King County Surface Water Design Manual, artificial turf is treated as impervious for threshold determination and runoff modeling: artificial turf without an underdrain is considered an impervious surface, and turf with an underdrain designed to collect stormwater runoff is also considered impervious. Artificial turf is further classified as a pollution-generating surface, and it is not permitted within a stormwater dispersion device. For recreational installations where the turf serves a playing surface, additional water beyond the calculated landscape water budget may be allowed with a specific application designation. Practically, a modest residential turf area is straightforward, but larger turf installations may push a project over impervious-surface thresholds that trigger stormwater review and drainage requirements. Homeowners installing turf should check whether the added impervious area requires drainage review under SDC 21.03.050 (Surface Water Management).