State law requires no new setback for an existing structure converted to an ADU. San Diego's code allows up to 150 sq ft of added space solely for access and usually does not require replacement parking, with a Beach Impact Area exception.
Last verified 2026-10-18. Rules change; the City of San Diego Development Services Department has the final word.
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San Diego Municipal Code 141.0302(b)(7)(D) gives an ADU made within an existing structure no City gross-floor-area maximum. It allows an additional 150 sq ft only to make ingress and egress possible.
San Diego Municipal Code 141.0302(b)(7)(D)Information Bulletin 400 requires a Coastal Development Permit for an ADU in the Coastal Overlay Zone when the project converts non-habitable space. Confirm whether the proposed garage conversion meets the City's coastal conditions.
City of San Diego Information Bulletin 400, Coastal Development Permit Requirement| Type | Est. all-in cost | Est. rent |
|---|---|---|
| Garage conversion | $232-$377 per sq ft of garage (about $93,000-$151,000 for a 400 sq ft garage) | $1,750-$2,525/mo |
Estimates for a first conversation, not bids or appraisals. Source: LotUpside price book sd-2026-10. Provisional estimate: rent, build-cost and value figures come from San Diego price lists and City fee schedules and have not yet been checked against a local builder's quote. They are not quotes, bids or appraisals.
Ask the City of San Diego Development Services Department before you rely on these.
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Government Code 66314(d)(7) requires no new setback for an existing accessory structure converted to an ADU. City Information Bulletin 400 says California Building Standards Code requirements may still affect how close an ADU can sit to a lot line.
Usually no. San Diego Municipal Code 141.0302(b)(10)(C) waives replacement of garage parking unless the lot is in the Beach Impact Area of the Parking Impact Overlay Zone and outside a transit priority area.
City Information Bulletin 400 requires a Coastal Development Permit for an ADU in the Coastal Overlay Zone that converts non-habitable space. San Diego Municipal Code 141.0302(a)(7) adds conditions for converting an existing structure in that zone.
Neither. It is a screening from public records, not professional advice, and not a survey, soils report, appraisal, loan offer or permit; every number is an estimate. A licensed designer confirms the final plan, and your city or county gives final approval.