California Remodel Cost vs. Value › Projects
Caissonix report · 2026 · 13 California cities
Does an ADU Add Value in California? ADU Cost vs. Value
A peer-reviewed Los Angeles study (Brueckner and Thomaz, 2024) found an ADU raised the value of just-sold homes by close to 9%, and 7%–8% across all homes. On the City of Los Angeles median owner-occupied home value of $951,800 (Census ACS 2025), 7%–9% is $66,600–$85,700, against our likely cost of $279,900 for this project in Los Angeles.
The study covered every kind of ADU, many of them smaller or older than a new unit, and a sale price does not count rent collected while you own the home. We show a dollar figure for Los Angeles only, because that is where the study measured. Our likely cost runs from $262,900 in Bakersfield to $305,000 in San Jose for the same job.
Not an appraisal, a broker price opinion or a prediction of a sale price. Costs are budget estimates, not a bid, appraisal, or insurance claim valuation. Pilot.
The project we priced
Detached ADU (600 sq ft). New 600 sq ft detached ADU with one bathroom and a full kitchen, mid-range finishes, permits, design, fees and utility hookups.
Same scope in every city, mid-range finishes. Your own home, size and finish choices will differ.
Detached ADU (600 sq ft): cost by California city
| City | Likely cost | Range | Share of median home value |
|---|---|---|---|
| San Francisco (Bay Area) | $303,100 | $253,400–$364,200 | 23% |
| Oakland (Bay Area) | $301,600 | $252,600–$361,000 | 34% |
| San Jose (Bay Area) | $305,000 | $256,200–$366,300 | 22% |
| Los Angeles (Los Angeles and Orange County) | $279,900 | $234,000–$334,400 | 29% |
| Long Beach (Los Angeles and Orange County) | $280,900 | $235,700–$331,900 | 32% |
| Irvine (Los Angeles and Orange County) | $276,900 | $232,600–$330,400 | 17% |
| San Diego (San Diego) | $276,500 | $233,000–$328,300 | 27% |
| Sacramento (Sacramento) | $270,600 | $226,800–$321,700 | 52% |
| Riverside (Inland Empire) | $266,700 | $224,800–$315,300 | 42% |
| San Bernardino (Inland Empire) | $266,000 | $222,800–$318,100 | 58% |
| Fresno (Central Valley) | $263,200 | $219,900–$317,600 | 66% |
| Bakersfield (Central Valley) | $262,900 | $221,200–$314,300 | 65% |
| Stockton (Central Valley) | $263,800 | $223,100–$315,100 | 59% |
Likely is the median of 4,000 simulated outcomes from our estimator; the range is the 10th to 90th percentile. Share of median home value compares the likely cost with the city's median owner-occupied home value (U.S. Census Bureau, ACS 2025 1-year, table B25077).
Resale value: what we can verify
| City | Value added | Range | Likely cost | Value ÷ cost | Confidence |
|---|---|---|---|---|---|
| Los Angeles | $76,100 | $66,600–$85,700 | $279,900 | 27% | Low |
Source: Brueckner and Thomaz, "ADUs in Los Angeles: Where are they located and by how much do they raise property value?", Real Estate Economics (2024). https://doi.org/10.1111/1540-6229.12471
Other cities (San Francisco, Oakland, San Jose, Long Beach, Irvine, San Diego, Sacramento, Riverside, San Bernardino, Fresno, Bakersfield, Stockton): no value figure yet. We do not stretch one city's result to another.
Questions
How much does a detached adu cost in California?
For the fixed scope on this page (New 600 sq ft detached ADU with one bathroom and a full kitchen, mid-range finishes, permits, design, fees and utility hookups), our likely cost runs from $262,900 in Bakersfield to $305,000 in San Jose. Your size, finishes and ZIP change it; the free estimator recalculates it line by line.
Does an ADU Add Value in California?
A peer-reviewed Los Angeles study (Brueckner and Thomaz, 2024) found an ADU raised the value of just-sold homes by close to 9%, and 7%–8% across all homes. On the City of Los Angeles median owner-occupied home value of $951,800 (Census ACS 2025), 7%–9% is $66,600–$85,700, against our likely cost of $279,900 for this project in Los Angeles.
Is this an appraisal?
No. It is an informational report: budget cost estimates plus the resale value evidence we can verify from public records and published studies. It is not an appraisal, a broker price opinion or a prediction of what your home will sell for. For a valuation, ask a licensed appraiser or a local real estate professional.
Caissonix California Remodel Cost vs. Value, 2026 pilot edition. Cost figures computed 2026-10-31 from engine 0.10.0, price book 2026-10-31.1. Not an appraisal, a broker price opinion or a prediction of a sale price. Costs are budget estimates, not a bid, appraisal, or insurance claim valuation. Get licensed contractor bids before you decide.