The parcel comes before the floor plan

An accessory dwelling unit is not guaranteed because a yard looks large. Confirm the parcel, jurisdiction, zoning, existing structures, access, slopes, easements, utilities, and applicable overlays. Separate an existing permitted unit from a garage conversion or future concept advertised as potential. Ask for documentation of any claimed permit and final approval.

Clairemont, North Park, and Vista offer different housing settings to investigate, not neighborhood-level ADU approval. Use the individual parcel as the unit of analysis.

City and County rules are different

The City of San Diego publishes its ADU and JADU requirements in Information Bulletin 400. County guidance applies to unincorporated areas; incorporated cities may have their own procedures. Do not use City rules for a County parcel or assume a nearby city's standards apply.

Start with the correct planning department. Ask about allowable units, setbacks, height, access, parking rules and exceptions, utilities, and permit steps for the proposed project. These details can change, so this guide intentionally does not promise a universal size or approval timetable.

Coastal, historic, and site conditions matter

Coastal overlays can change review requirements. Historic-resource issues, easements, steep terrain, drainage, fire access, sewer capacity, and utility work can also affect feasibility and costs. A standard plan does not eliminate site-specific work.

For a coastal purchase, read coastal home buying and ask whether Coastal Development Permit or local coastal program requirements apply. City guidance and the Coastal Commission's ADU material should be reviewed together where relevant.

Bring the right questions into your offer

  • Is the existing unit legally permitted and finaled for the claimed use?
  • Can a qualified designer or permit professional screen this exact parcel?
  • What records are missing, and how will they be obtained?
  • What utility and access work might be needed?
  • Do recorded restrictions or association rules require review?
  • What costs remain unknown before the offer deadline?

Do not pay for assumed rental income before checking both feasibility and financing. Use the ADU project budget and rental-income guide to evaluate the next steps.

Keep potential separate from certainty

A feasibility discussion is not a building permit, and a permit is not a completed rentable home. Negotiate and budget based on what exists and what has been documented. If the purchase depends on an ADU, discuss appropriate investigation protections with your agent and qualified advisers before committing.