California's ADU laws have changed the math on San Diego real estate. State legislation since 2020 removed most local restrictions — no minimum lot size, no owner-occupancy requirement for new construction permits, reduced setbacks, ministerial approval (no discretionary review). If you own a single-family property in San Diego, you almost certainly qualify to build an ADU.
Peak Builders has built ADUs across San Diego County. Here's what you need to know.
San Diego ADU Types
Detached ADU — a freestanding structure in your backyard with its own foundation, kitchen, and bath. Maximum privacy and rental value. California allows up to 1,200 sq ft for a detached ADU.
Attached ADU — built onto the side or rear of the main house, sharing one wall. Shares utilities more easily, slightly lower construction cost.
Junior ADU (JADU) — a conversion of an existing room within the main house, up to 500 sq ft with its own entrance and efficiency kitchen. Fastest and lowest-cost path if the layout works.
Garage conversion — converting an existing attached or detached garage into a legal dwelling unit. San Diego allows garage conversions without providing replacement parking under most circumstances. Popular in neighborhoods with older two-car garages that aren't being used for cars.
San Diego-Specific Considerations
Permit Process
San Diego has streamlined ADU permitting — most standard ADU projects go through ministerial approval, meaning no public hearing, no discretionary review board, no opportunity for neighbors to object. The city must act within 60 days of a complete application.
Solar Requirement
California Title 24 requires newly constructed ADUs above 500 sq ft to include solar panels. We handle the Title 24 energy calculation and solar system sizing as part of the permit package.
Coastal Zone
Properties in the Coastal Zone (roughly within 1 mile of the coast) have additional restrictions under the California Coastal Act. ADU permitting in the Coastal Zone can take longer and may have additional design constraints. We identify this at the initial consultation.
Fire Sprinklers
San Diego requires fire sprinklers in detached ADUs over 500 sq ft when the main house has sprinklers. If the main house doesn't have sprinklers, sprinklers are only required in ADUs over 3,600 sq ft (effectively never).
Financing
ADU construction loans and HELOCs are the most common financing paths. California's ADU financing programs have expanded in recent years. We can connect you with local lenders who specialize in ADU financing.
Getting Started
The first step is a free feasibility consultation at your property. We review your lot, identify what type and size ADU is possible, and give you a clear picture of what's involved before you commit to anything.
Call (619) 330-8185 or book online.
