San Diego County ADU Guide

City of San Diego

Standard-plan and custom ADU paths are available. A standard building plan still requires property-specific site, zoning, utility, and agency information.

Official source verified 2026-08-18Official jurisdiction resource ↗
01 / Plan path

Choose the right production starting point.

Standard-plan and custom ADU paths are available. A standard building plan still requires property-specific site, zoning, utility, and agency information.

Express PlanStarting at $4,500

For a qualifying jurisdiction preapproved plan adapted into the property-specific architectural production set.

Custom PlanStarting at $6,500

For an original floor plan and architectural production set developed around the property and homeowner.

02 / Size + fee checkpoints

Size affects more than floor area.

Local pathways may allow ADUs up to 1,200 square feet. The selected statutory pathway, unit type, property conditions, and objective standards control.

The City currently identifies special Development Impact Fee treatment for the first two ADUs. School, utility, plan-check, and other service charges require separate confirmation.
500 SFConfirm school-fee assessment rules750 SFState impact-fee protection checkpoint1,000 SFTwo-bedroom state minimum allowance1,200 SFCommon local upper-range checkpoint
03 / Site conditions

Property conditions can change the path.

  • Development Impact Fee and unit-count treatment
  • Coastal Zone and coastal appeal area
  • Fire access and water supply
  • Historic, environmentally sensitive, or other mapped constraints
  • Existing dwelling and utility records
04 / Consultant screen

Likely disciplines to evaluate.

  • Structural engineering
  • Title 24 energy documentation
  • Survey where boundaries or topography require it
  • Civil, geotechnical, or fire consultation when triggered

Consultants are retained only when required by the property, design, or reviewing agency. Their proposals and coordination are separate from the architectural production fee unless stated otherwise in the agreement.

05 / Property-specific next step

Turn the guide into a preliminary project report.

Enter the address to screen jurisdiction, mapped constraints, likely agencies, drawing requirements, consultants, and the preliminary fee path.

Check the property →Email Bennett Design Studio →
Important: This guide is general planning information, not a zoning determination, permit approval, fee quote, or guarantee of feasibility. Current parcel records, adopted codes, agency interpretations, utility requirements, site investigation, and written agency confirmation control.