Costa Mesa, CA Accessory Structures: Shed & Carport Rules (2026)

Section 13-33 governs accessory buildings and structures citywide. Any accessory building or structure placed closer than 75 feet from the front property line, or on the front half of the lot (whichever distance is less), must go through planning division review to confirm it is adequately screened and compatible with the main structure on the property; this catches sheds, detached garages, and workshops built forward on a lot rather than tucked in back. The section separately allows underground structures, including fallout shelters, to be built on any part of the lot as long as they stay below grade, with no front-yard screening review required since they aren't visible.

Shipping containers, however, are prohibited outright in residential zones with no exception listed. 5 feet tall or less in the R1 zone, or 15 feet or less in the other residential zones, can sit with a zero side setback and, outside R2/R3 corner lots, a zero rear setback as well, rather than the 5-foot side and 10-to-20-foot rear setbacks that apply to main buildings. Rear yard coverage for accessory buildings is capped separately at 50% of the rear yard area under § 13-32. A shed proposed within the front 75-foot zone still needs planning review even if it meets every setback and coverage number.