How much does it cost to build an ADU in San Diego? The usual ADU (companion unit) job filed with San Diego is $127,372, from 1,238 priced permits (October 2023 through September 2026); the middle half of firms file between $105,805 and $174,174. A filed value is what the contractor wrote on the permit, not a quote or the final bill.
The usual ADU (companion unit) job filed with San Diego is $127,372, from 1,238 priced permits, October 2023 through September 2026. The middle half of firms usually file between $105,805 and $174,174. Half of jobs were filed for less, half for more. A filed value is what the contractor wrote on the permit, not a quote or the final bill. An ADU (companion unit) permit here usually takes 442 days from issue to final inspection. How long permits take →
Approximately, from each firm's own spread: every firm's range of filed values, weighted by its 1,238 priced permits across 626 firms, pooled into one. Half of San Diego ADU (companion unit) permits were filed between $80,300 and $188,000.
| Percentile | Filed value | Reads as |
|---|---|---|
| 10th | $55,100 | 1 in 10 permits filed below |
| 25th | $80,300 | 1 in 4 filed below |
| 50th | $129,000 | the middle permit |
| 75th | $188,000 | 1 in 4 filed above |
| 90th | $267,000 | 1 in 10 filed above |
Firms split into thirds by the usual value of the homes they work on, with each third's usual filed value weighted by permits. Home values: San Diego County assessed values (Prop 13, below market).
| Firms working on | Usual home value | Usual filed value | Firms | Permits |
|---|---|---|---|---|
| Lower third | under $653,520 | $136,252 | 206 | 365 |
| Middle third | $653,520–$1,066,465 | $125,766 | 207 | 484 |
| Upper third | $1,071,512 and up | $124,432 | 207 | 398 |
Top 10 by permits in the last 12 months. Usual is each firm's middle filed value; middle half is the range its middle half of jobs were filed in. Busy is not the same as careful: pick what you value to build a list.
| Firm | Permits | Last 12 mo | Usual | Middle half | Finished |
|---|---|---|---|---|---|
| 1PLUS Studio | 36 | 28 | $186,253 | $113,069–$213,856 | 6 of 8 |
| Ballow Construction Inc | 13 | 13 | $268,219 | $216,991–$346,581 | — |
| Infill Innovation Inc | 13 | 13 | $139,162 | $139,162 | — |
| Mankind Investment Group | 11 | 11 | $266,728 | $266,728 | — |
| Snapadu | 27 | 10 | $154,299 | $128,974–$209,324 | 93.9% |
| Better Place Remodeling | 32 | 8 | $80,752 | $65,402–$121,974 | 85.5% |
| Waypoint Construction | 8 | 8 | $157,552 | $157,552–$196,691 | — |
| Marwan Alrifai | 7 | 7 | $263,249 | $249,333–$263,249 | — |
| RL Remodeling | 7 | 7 | $99,402 | $71,072–$118,039 | — |
| Waypoint Development LLC | 7 | 7 | $272,526 | $267,887–$638,657 | — |
Line your quote up against the file. In San Diego, 1 in 10 ADU (companion unit) filed values sit under $55,100, the middle half between $80,300 and $188,000, and 1 in 10 over $267,000.
San Diego files the fewest ADU (companion unit) permits in September (58 against an average month of 100) and the most in April (134). If you can choose, ask for quotes in a quiet month. We have no prices by month, so this is about crews' schedules, not a discount. When each trade is busiest in San Diego →
Source: City of San Diego Development Services approvals. The window is October 2023 through September 2026; a permit filed after that isn't here yet.
Usual is the middle permit: half were filed for less, half for more. Only permits with a filed value count; a value of $0 or none is left out.
The spread is approximate: we keep seven points of each firm's own range of filed values, not every permit, and pool them.
Nobody paid to be on this page and nobody can. How the records work in San Diego →
ADU (Companion Unit) cost in other cities: Nashville Raleigh Denver Honolulu Palo Alto Bellingham San Francisco Anaheim Marin County (unincorporated) Sacramento County (unincorporated)
Other job costs in San Diego: Remodel & Alteration · Addition · Pool & Spa · Damage Repair · New Home · Foundation & Seismic Retrofit · Patio Cover, Garage & Accessory Structure