Shed Rules: Castro Valley vs Fremont

How tall can a shed be in unincorporated Alameda County?

Section 17.52.260 of the Alameda County Code limits a detached accessory building in any R district to one story and a maximum height of fifteen feet. A shed that exceeds either limit needs a different zoning approval and should be discussed with the Alameda County Planning Department at (510) 670-5400 before construction.

Do I need a building permit for a small shed?

Title 15 of the Alameda County Code adopts the California Residential Code, and CRC Section R105.2 generally exempts one-story detached accessory storage sheds of 120 square feet or less from a building permit. Zoning rules in Section 17.52.260, the underlying R-district setbacks, and any electrical or plumbing work in the shed still require county review. Confirm the current threshold with Building Inspection.

How close can my shed be to my house?

Section 17.52.260 requires at least six feet between a detached accessory building and any other building on the same lot in an R district. The shed must also satisfy the side and rear yard setbacks of the property's specific R district under Title 17.

Can I put a Tuff Shed on a concrete pad?

Yes. A prefab shed 120 sq ft or smaller on a concrete slab with 3-foot setbacks is allowed without a permit. A slab larger than the shed footprint may trigger separate impervious-surface review.

Does a she-shed with AC need a permit?

Yes. Any electrical or HVAC service makes it a habitable-adjacent accessory structure and requires a building permit, electrical permit, and inspection regardless of floor area.