Walnut Creek, CA Outdoor Lighting: Dark Sky Rules (2026)

Walnut Creek Municipal Code Title 10 (Zoning) includes outdoor lighting standards intended to minimize light trespass, glare, and sky glow while maintaining safety. For commercial, industrial, and multi-family properties, lighting must be fully shielded (dark-sky compliant) with no direct light emission above the horizontal plane of the fixture. Maximum illumination levels at property lines are typically capped (e.g., 0.5 foot-candles at residential boundaries). Parking lot lighting must use cutoff fixtures and may be required to dim or shut off after business hours. For single-family residential, outdoor lighting must be directed away from adjacent properties and public rights-of-way. Floodlights visible from neighboring residential windows can be cited as a nuisance. New development subject to design review typically has lighting plans reviewed for dark-sky best practices. Walnut Creek's proximity to Mount Diablo State Park (which has significant astronomical interest) provides additional motivation for light pollution reduction, though the city has not adopted a formal IDA Dark Sky ordinance. LED color temperature is increasingly regulated; warmer color temperatures (3000K or lower) are encouraged.