01 / Plan pathChoose the right production starting point.
La Mesa publishes pre-approved ADU plans. Using one still requires a project-specific site plan, Title 24 energy calculations and supplemental documents, submitted through the City's permitting portal.
Express PlanStarting at $4,500For a qualifying jurisdiction preapproved plan adapted into the property-specific architectural production set.
Custom PlanStarting at $6,500For an original floor plan and architectural production set developed around the property and homeowner.
Size affects more than floor area.
The City publishes an ADU guidebook and a JADU quick-info sheet, updated to reflect changes in state ADU law. Confirm the current objective standards with the Planning Division.
Energy calculations are required for all projects, and the City indicates a soils report is required above 500 square feet. Confirm current fees with Planning at 619-667-1177.
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 conditionsProperty conditions can change the path.
- Whether a pre-approved plan suits the lot
- Zoning and lot configuration
- Soils report trigger above 500 square feet
- Fire access and utility service
04 / Consultant screenLikely disciplines to evaluate.
- Structural engineering
- Title 24 energy documentation
- Soils or geotechnical engineer where the size trigger applies
- Survey where boundaries require it
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 stepTurn 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.
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.