Issaquah, WA Outdoor Lighting: Light Trespass & Shielding (2026)

Issaquah Land Use Code § 18.610.070 is the lighting rule for homes. It applies to a residential use that contains 10 or fewer dwelling units and does not have an outdoor common area. The core trespass sentence is in subsection (B)(1): outdoor lighting may not be aimed onto adjacent properties, and the code expressly includes low voltage and line voltage landscape lighting. Shielded directional flood lighting must be aimed so that direct glare is not visible from adjacent properties, and security lighting activated by motion sensors must be set to automatically time out and shut off.

Subsection (B)(2) caps mounting height: no luminaires may be placed at more than 15 feet above grade. Subsection (B)(4) adds the shielding mandate. Unshielded luminaires are prohibited except as identified in Table 18.610.070(C), and all outdoor luminaires must be fully shielded. The table sets a maximum for each fully shielded luminaire of 630 lumens in LZ 0 and 1,260 lumens in LZ 1, LZ 2 and LZ 3. One partly shielded or unshielded luminaire is allowed at the main entry, capped at 420 lumens in LZ 1 and 630 lumens in LZ 2 and LZ 3, and not allowed in LZ 0.

The scope has limits. Section 18.610.040(A)(1) exempts all new and replacement lighting for existing structures on single-family lots from the chapter's standards, though it notes such lighting can still be regulated under federal law, state law, or other chapters of the Issaquah Municipal Code. For nonresidential and larger multifamily sites, § 18.610.050(A)(9) is the numeric spillover rule: light at any property line or project boundary cannot exceed three-tenths footcandles in light zones LZ 0, LZ 1 and LZ 2, or eight-tenths footcandles in LZ 3. Complaints are handled under § 18.610.090(B), where the City can have lighting evaluated by a consultant.