Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your San Francisco ADU cost →Building an ADU in San Francisco costs between $200,000-$450,000 for new construction, with per-square-foot costs averaging $300-$500. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $120,000-$250,000, while prefab/modular ADUs fall in between at $150,000-$350,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | $5,000-$20,000 depending on scope |
| Impact Fees | Waived for units under 750 sq ft |
| Site Prep & Foundation | $10,000 – $35,000 |
| Framing & Structure | $15,000 – $45,000 |
| Plumbing | $8,000 – $20,000 |
| Electrical | $5,000 – $15,000 |
| HVAC | $3,000 – $8,000 |
| Interior Finishes | $15,000 – $40,000 |
Quotes for the same ADU commonly vary 20–40% between builders. Get up to 3 free quotes from ADU builders serving San Francisco — no obligation.
Get San Francisco builder quotes →Permit fees in San Francisco are $5,000-$20,000 depending on scope. The review timeline is 60-day review period (state-mandated), with plan check: Expedited plan check available. Impact fees are Waived for units under 750 sq ft. Pre-approved plans: Yes — SF has pre-approved ADU plan sets.
| 1-Bedroom Rent | $2,200-$3,200/month |
| 2-Bedroom Rent | $2,800-$4,000/month |
| Annual Rental Income (est.) | $32,400/year |
| Payback Period (est.) | 10.0 years |
| Short-Term Rental | Not allowed — SF ADUs and JADUs are ineligible for the Short-Term Rental program; minimum 30-day rentals only |
| Overall ROI Estimate | 5-8% annual return |
A typical ADU in San Francisco generates approximately $32,400 per year in rental income based on average 1-bedroom rents. At an average construction cost of $325,000, the estimated payback period is 10.0 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in San Francisco and varies by market (often less than build cost).
1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in San Francisco: $120,000-$250,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $150,000-$350,000.
3. Pre-approved plans — available in San Francisco, which can save $3,000-$10,000 in design costs and 2-3 months in review time.
4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.
5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.
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