Walnut Creek, CA Accessory Structures: Shed Rules (2026)

Walnut Creek follows the California Residential Code exemption in Section R105.2 allowing one-story detached accessory structures used as tool/storage sheds to be built without a building permit when they do not exceed 120 sq ft of floor area. Anything larger, or any structure with electrical service, plumbing, mechanical equipment (like HVAC), or intended for human habitation, requires permits from the Community Development Department. Regardless of building permit exemption, all sheds must comply with Walnut Creek's zoning regulations: generally 3 feet minimum setback from side and rear lot lines in residential zones, must be located behind the front-yard setback (cannot sit in the front yard of most residential lots), and total lot coverage of all structures cannot exceed the zone's maximum. Height limits for accessory structures in residential zones are typically 12 feet for pitched roofs, less for flat roofs. HOAs often impose stricter standards — color, materials, visibility from the street. Sheds must not encroach into easements (drainage, PUE). In fire hazard zones, sheds are subject to defensible space and Zone 0 ember-resistant rules. Sheds cannot be used as dwellings; that would require converting to a permitted ADU under AB 68/881.