San Jose permitted 3,019 ADUs from 2013 to 2024 — among the most active markets in California. Here's what it costs, what's allowed, and who builds them.
All-in design-build estimates (architecture + permits + construction + soft costs). Real quotes vary by lot conditions, finishes and contractor — get at least three before signing.
Per-square-foot ranges reflect 2026 pricing in the bay area market. Permit fees ($5–25k), site work ($10–40k) and high-end finishes can push totals 20–40% higher. See cost methodology for the full regression model and the 8 California builder-pricing sources it's calibrated against.
California state law sets a floor that every city must meet. San Jose may allow more than the minimums shown — confirm with the San Jose planning department before finalising plans. See how we verify city-specific ordinance data.
| Rule | Standard |
|---|---|
| ADUs allowed on single-family lot | Yes — required by state law |
| Max units per lot | 1 ADU + 1 JADU on single-family; up to 2 detached ADUs + JADU on multifamily |
| Owner-occupancy required | Not allowed to require for ADUs (state preempts) |
| Side setback (detached) — local | 4 feet |
| Rear setback (detached) — local | 4 feet |
| Max height — local | 16 ft |
| Off-street parking — local | None required if within 0.5 mi of public transit (state law applies in most metros) |
| Max ADU size — local | 1200 sqft |
| Min lot size | No minimum required by state |
| Permit timeline (ministerial) | 60 days from complete application (state law) |
Source: San Jose planning department. Verified April 2026.
Annual ADU permits issued, 2013–2025. Sources: Big West Coast ADU Dataset for 2013–2022 and the California HCD Annual Progress Report (April 2026 snapshot) for 2023–2025.
*Partial year. HCD's 2025 APR snapshot (April 2026) reflects jurisdictions that filed by the April 1 deadline; remaining cities continue to report through mid-2026.
Active CA-licensed B-class general contractors with ADU-specialist branding, sourced from the CSLB Public Data Portal snapshot from April 28, 2026. Click any license number to verify current status at the CSLB Instant License Check — status can change at any time. See builder-directory methodology.
California state law (post AB-2221, AB-976, AB-1033, AB-1332) sets a baseline that every city must meet — but cities can be more permissive. Here's where San Jose departs from the state floor:
Each bullet above is verifiable against the linked planning-department ordinance — never rely on a third-party site (including this one) as the authoritative source for a permit decision.
Between 2013 and 2024, San Jose issued 3,019 ADU permits — 1.9% of California's 160,307 cities-only lifetime total over the same window. The peak year was 2024 at 558 permits.
The most recent complete year (2024) saw 558 permits, a +19% change from the prior year. That represents 1.6% of California’s 34,852 cities-only 2024 permits. That's 37.2× the 15 permits issued in 2013, when San Jose's post-state-preemption growth curve began.
What the 2024 peak tells you: ADU activity in San Jose has matured beyond the explosive 2017–2020 phase. The growth rate has compressed from the double-digit-per-year jumps that followed each state preemption package (SB 1069 + AB 2299 in 2017, SB 13 + AB 68 + AB 881 in 2019) to a steady high-single-digit-or-flat baseline. That's a stable-not-cooling market — design and permit timelines are typical of any settled construction sector, builder capacity exists, and permit-cost predictability is higher than during the 2018–2020 surge.
6 CSLB-licensed builders in our directory list a San Jose mailing address and have ADU-keyword branding in their business name. Average tenure on the licence is 9.3 years (longest-tenured: 36 years). Business structure mix: 5 corporations, 1 sole proprietor. All builders on this list have posted the $25,000 California statutory minimum — the standard for class-B contractors. This is a precision-over-recall slice: many quality San Jose ADU builders sit in the broader 102,004-strong active-B-license pool without ADU branding, and won't surface here. The builder cards above are a starting point for diligence, not the full universe.
California state ADU law has tightened materially in the last three years. Even if San Jose's local ordinance text hasn't been amended since the original adoption, these state-level changes preempt the local code and apply automatically:
The Berkeley ADU Scorecard 2020 gave San Jose an "B" grade against the then-current state law. Each of the four state-law changes above has either improved San Jose's effective regime or backstopped it — the Scorecard is now best read as a historical snapshot of municipal intent rather than current law.
Most San Jose ADU projects fall in a $100,000–$400,000+ range, all-in (design + permits + construction). The big drivers are size, type (detached costs more than a garage conversion), and finish level. See the per-type cost table above for typical ranges in this market.
Yes — every ADU in California requires a building permit. San Jose processes ADU applications under the state's 60-day ministerial review rule (no public hearings, no discretionary review for code-compliant designs). Permit fees vary but typically run $5,000–$25,000 depending on size and impact fees.
State law guarantees a minimum allowance of 850 sqft (studio/1BR) or 1,000 sqft (2+BR). Many California cities allow larger detached ADUs — check the San Jose planning department or the ordinance link in our rules table above for the local maximum.
No, not for an ADU. AB-976 (effective 2023) extended the state's ban on owner-occupancy requirements for ADUs through January 1, 2030 — California cities may not require an owner to live on the property as a condition of permitting an ADU during that window. JADUs are different: owner-occupancy of either the primary residence or the JADU itself is required by state law throughout the JADU's life.
A JADU (Junior ADU) is a unit ≤500 sqft created within an existing single-family home, sharing a wall with the main residence. JADUs are cheaper and faster to build, but they require owner-occupancy of either the main house or the JADU. Most homeowners build a separate ADU for rental flexibility.
According to the California ADU permit dataset compiled by BuildinganADU.com, San Jose permitted 558 ADUs in 2024, the peak year on record (2013–2022). California-wide ADU permits have grown roughly 20× over that period — homeowner demand is outpacing every other housing-supply tool the state has tried.
UC Berkeley's Center for Community Innovation graded San Jose's ordinance B in their 2020 ADU Scorecard, scoring the 2018 ordinance text. The mean grade across California was C+, so anything above that ranked as relatively homeowner-friendly at the time. This is historical, not current law: state-level updates since 2020 (AB-2221, AB-976, AB-1033, SB-477, SB-1211 and others) have raised the statewide floor and many cities have rewritten their local ordinances since the 2020 grading. Always check the current ordinance text linked above for what applies to a project you're about to start.