Issaquah, WA Landscaping Rules: Artificial Turf (2026)

Issaquah regulates artificial turf as a performance standard, not a size cap. Subsection (I) of Land Use Code § 18.606.040, Planting and vegetation standards, says artificial or synthetic turfs must comply with the best available science to ensure no toxic run-offs or adverse environmental impacts. Its example is specific: some turfs use 6PPD quinone or microplastics that have harmful effects to aquatic ecosystems. The subsection prints no square-foot limit, no product list, and no setback for turf.

The subsection sits among the planting standards that apply to landscape areas under Chapter 18.606. Under § 18.606.020 the chapter applies to new development, subdivision of property, development or redevelopment in, adjacent to, or affecting critical areas, and any redevelopment or project that increases impervious surface area by 20 percent or more. Section 18.606.030 exempts single-family use lots with a detached single-family home, middle housing developments, accessory dwelling units, and small projects of five or fewer new trees or 1,000 square feet of landscaping from the chapter's permitting and bonding requirements.

Neighboring rules shape how turf is treated on a site. Irrigation systems serving turf-grass exceeding a slope of 3:1 must be low-volume subsurface systems with a distribution uniformity of not less than 0.90 (§ 18.606.060(H)). Berms planted with sod lawn must be no steeper than a 3:1 ratio (§ 18.606.040(J)(1)). The impervious surface section, § 18.404.040, singles out athletic artificial turf: athletic artificial turf that acts as a stormwater facility is not considered impervious, while athletic artificial turf without subsurface stormwater facilities is considered impervious. That rule is written for athletic turf, not for residential lawn replacement.