Real ADU pricing.
No placeholder quotes.
Four tiers, honest ranges, and the hidden line items most builders refuse to mention. Then a free Property Potential Report with your actual lot-specific number.
Four ways to make the math work.
These are all-in 2026 ranges for San Diego County — design, permits, and construction. Your Property Potential Report narrows the number to your lot.
Garage Conversion
350–600 sqft · 3–5 months build
Fastest path to an ADU. Best when the garage is unused and budget is the priority.
1 BR / 1 BA Detached
500–650 sqft · 5–7 months build
The classic income ADU. Highest cap rate on the smallest footprint.
2 BR / 1 BA Detached
700–900 sqft · 6–8 months build
Sweet spot for family rentals and multigenerational use.
2 BR / 2 BA Detached
900–1,200 sqft · 7–9 months build
Maximum rent, maximum resale lift. Often 1.3×+ cost added to property value.
Ranges assume a permitted ADU with standard finishes (LVP floors, quartz counters, mid-grade appliances). Premium finishes add 8–15%. Very small or oddly-shaped lots can run above these ranges.
Every dollar, accounted for.
The breakdown below is based on a typical $400K detached ADU in San Diego. Knowing where your money lives is the first step to a real conversation.
What most builders leave out of the quote.
When a quote looks too good to be true, one of these six is almost always missing. We price them in on day one — in writing.
Sewer lateral capacity
An undersized or aging lateral can trigger a street cut — $8K–$18K.
Main electrical panel upgrade
Most older SD homes need a 200A panel upgrade to support an ADU. $6K–$14K.
SDG&E transformer capacity
If the block transformer is at capacity, SDG&E may require an upgrade. $0–$15K.
Structural engineering
Sloped lots, soft soil, or non-standard framing need a stamped engineer. $3K–$9K.
Fire sprinklers
If the main house is sprinklered, the ADU typically needs them too. $8K–$14K.
Coastal / historic overlays
Coastal Development Permits + historic review add design, engineering, and timeline.
What can your backyard do?
Drop your address and a goal. We'll send a first-read within one business day and a full Property Potential Report within two weeks — on us.
- ✓ Zoning + setback analysis
- ✓ Rent projection for your lot
- ✓ Ballpark build cost
- ✓ No obligation, no spam
Common cost questions.
01 How much does an ADU cost in San Diego?
Most detached ADUs in San Diego County land between $175,000 and $450,000 all-in (design, permits, construction) for 500–1,200 square feet. Garage conversions typically run $105,000–$250,000. Your ADU Property Potential Report gives you a real, lot-specific number within two weeks.
02 What financing options exist for ADUs?
HELOC, cash-out refi, construction-to-permanent loans, DSCR investor loans, and several state and local ADU grant programs. We introduce every client to three to four vetted lenders who specialize in ADU construction.
03 What’s the ROI on a typical San Diego ADU?
Most of our completed ADUs cash-flow at an 8–12% cap rate on construction cost and add 1.2–1.5x of their build cost in property value. Your Property Potential Report gives you real numbers for your specific lot.
Ready for your real number?
Two weeks. One report. No placeholder quotes.