San Jose has seen rapid ADU growth driven by Silicon Valley housing demand. The city follows CA state law closely and has added local incentives to encourage ADU construction.
Zoning & Size Requirements [1]
Yes — San Jose allows ADUs. A detached ADU can typically be up to 1,000 sq ft under current California and San Jose zoning rules.
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| Allowed Zones | Any zoning district where the site has a legally-built, permitted main residence - single-family, duplex or multifamily. Not restricted to the named residential districts, so listing R-1/R-2/R-M/R-MH understates where ADUs are allowed. Practical gating is by property condition rather than zone: an active Code Enforcement case must be resolved before plans are accepted, and flood, geohazard/liquefaction/landslide, historic and Wildland-Urban Interface designations add design requirements or clearances rather than prohibiting the ADU. |
| Max Size (Detached) | Depends on which standards track the applicant chooses. CITY Development Standards (SJMC 20.80.175): 1,000 sq ft on lots under 9,000 sq ft; 1,200 sq ft on lots over 9,000 sq ft. STATE Development Standards (SJMC 20.80.176): 800 sq ft on any lot. Minimum size 150 sq ft under either track. The tracks cannot be mixed. Same size table applies on duplex/multifamily lots under the City track. |
| Max Size (Attached) | CITY Development Standards: up to 50% of the existing primary dwelling living area, capped at 1,000 sq ft on lots under 9,000 sq ft and 1,200 sq ft on lots over 9,000 sq ft. STATE Development Standards: 800 sq ft. Minimum 150 sq ft. Under the State track an attached ADU is prohibited if there is an existing or proposed conversion ADU. City track also requires the attached ADU's front door to be on a different facade from the main home. Note the 50% cap cannot be applied to force an ADU below the state floors in Gov. Code 66321(b)(2). |
| Max Size (JADU) | 500 sq ft maximum, 150 sq ft minimum. Must be built within the existing footprint of a single-family home (including converting an attached garage) or within a proposed new single-family residence, and must comply with SJMC 20.80.178. Same 500 sq ft cap under both the City and State tracks. |
| Max Height | CITY Development Standards, single-family lot: detached ADU 18 ft for a first story, 25 ft for a second story; attached ADU 25 ft; maximum 2 stories either way. CITY standards on duplex/multifamily lots: 25 ft detached and 25 ft attached, maximum 2 stories. STATE Development Standards: attached 25 ft, detached 18 ft, plus up to 2 additional feet to accommodate a pitched roof; on duplex/multifamily 18 ft (+2 ft pitch). Our current '24 ft' is wrong and the '16 ft if a JADU already exists' clause does not appear in the city's standards at all. |
| Max Units | Single-family property: 1 ADU (detached or attached) plus 1 JADU - correct as we have it. Duplex/multifamily property, which our record omits entirely: under the STATE track, up to 8 detached ADUs on a lot with an existing multifamily dwelling (never more than the number of existing primary units), or up to 2 detached on a new/proposed multifamily dwelling; plus conversion ADUs of at least 1 and up to 25% of existing units (the city's worked example: a 20-unit apartment could have 4 conversion ADUs). Under the CITY track on duplex/multifamily, only 1 ADU (detached or attached). |
Setback Requirements [1]
San Jose requires a rear setback of about 0 ft for a detached ADU, and no additional parking is required. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | CITY Development Standards, detached ADU: 0 ft for the first story, 4 ft for a second story. STATE Development Standards: 4 ft. On duplex/multifamily lots the City track is 0 ft first story / 4 ft second story detached and 0 ft attached. Conversions of existing structures have no rear setback requirement under the State track. City-track detached ADUs must also keep a minimum 6 ft separation from the main home and must not cover more than 40% of the rear yard. |
| Side Setback | CITY Development Standards, detached ADU: 0 ft for the first story, 4 ft for a second story. STATE Development Standards: 4 ft. Attached ADUs and JADUs under the City track have no stated side setback beyond meeting minimum Building and Fire Codes. On duplex/multifamily lots the City track is 0 ft first story / 4 ft second story detached, 0 ft attached. |
| Front Setback | Per Table 20-60 of the zoning code, which varies by zoning district, under both the City and State tracks. Under the State track the front setback may be encroached if no other option enables a minimum 800 sq ft ADU on the site. Under the City track a detached ADU must additionally be sited behind the main home or at least 45 ft back from the front, whichever the zoning district requires. Conversions have no front setback requirement under the State track. The specific per-zone figures in Table 20-60 could not be read (see confidence note). |
| Parking Required | None. The city states 'None' for parking under both the City and the State development standards, on single-family, duplex and multifamily properties alike. Replacement parking is not required when a garage or carport is converted to an ADU. |
| Owner Occupancy | Not required for an ADU. For a JADU, owner-occupancy of the main home is required ONLY where the JADU does not have its own sanitation facilities; a JADU with its own bathroom carries no owner-occupancy requirement. Where it applies, it is secured by a recorded deed restriction (Form 313 JADU Deed Restriction Agreement, which the County Recorder requires to be wet-signed). ADU applicants must separately sign Form 312 ADU Property Owner Declaration - a declaration, not an occupancy requirement. Rentals of under 30 days are not permitted for either. |
| Min Lot Size | No minimum lot size (the former 3,000 sq ft minimum was removed effective January 1, 2020). Note the city does impose a minimum ADU SIZE of 150 sq ft under both the City and State tracks, which is a genuine local standard our record does not carry. |
Permit Process & Fees [2]
An ADU permit in San Jose goes through a ministerial, by-right review. Typical timeline: The city's own published figure is that the first round of building review typically takes 20 business days, with complete and accurate plans staying within one or two review cycles. Preapproved-plan projects may receive same-day permit issuance at the scheduled plan review meeting. The 60-day figure in our record is the state ministerial deadline (Gov. Code Chapter 13 / SB 543), not a San José-published processing time, and should not be presented as a city fact. The city flags the missing water-company flow letter as a main cause of delay.. Permit fees: City building permit fees, FY 2026-27 Building and Structure Permits Fee Schedule, effective August 10, 2026. ADU 0-750 sq ft: permit issuance $422, plan review $1,137, inspection $1,732 (total $3,291). ADU 751-1,200 sq ft: permit issuance $633, plan review $1,950, inspection $2,520 (total $5,103). Permit issuance includes addressing assignment for the unit; inspection includes the meter release inspection. Modular fees are 10% lower for plan review and 20% lower for inspections. Separately, an optional preliminary virtual meeting with a planner is billed at the Planning Division's hourly rate of $398/hour with a 30-minute minimum (i.e. $199). These are city permit fees only and exclude school/parkland impact fees, construction taxes, and construction cost.
| Approval Process | Ministerial, run through a defined six-step city process. Step 1: complete the ADU Universal Checklist (Bulletin #210) and optionally book a preliminary virtual meeting with a planner ($398/hour, 30-minute minimum). Step 2: prepare plans per Bulletin #211. Step 3: apply online via SJPermits.org and name an 'ePlan Applicant'. Step 4: upload the submittal package to SJePlans - must include Bulletin #211 plans, Bulletin #213 inspection checklist, Title 24 energy and CalGreen documents, Form 302 address assignment, Form 312 owner declaration (or Form 313 for a JADU), and a water-flow letter from the water company. Step 5: three-phase review - Prescreen (invoice for initial plan review fees), Plan Review (comment/resubmittal cycles), Issuance Review (residual plan review, inspection, school and parkland fees paid, then permit issues). Step 6: construction and inspections. Preapproved-plan projects use a separate expedited path with a dedicated City review team. Multifamily and AB 2533 legalization projects are routed through the ADU Ally team. |
| Review Timeline | The city's own published figure is that the first round of building review typically takes 20 business days, with complete and accurate plans staying within one or two review cycles. Preapproved-plan projects may receive same-day permit issuance at the scheduled plan review meeting. The 60-day figure in our record is the state ministerial deadline (Gov. Code Chapter 13 / SB 543), not a San José-published processing time, and should not be presented as a city fact. The city flags the missing water-company flow letter as a main cause of delay. |
| Permit Fees | City building permit fees, FY 2026-27 Building and Structure Permits Fee Schedule, effective August 10, 2026. ADU 0-750 sq ft: permit issuance $422, plan review $1,137, inspection $1,732 (total $3,291). ADU 751-1,200 sq ft: permit issuance $633, plan review $1,950, inspection $2,520 (total $5,103). Permit issuance includes addressing assignment for the unit; inspection includes the meter release inspection. Modular fees are 10% lower for plan review and 20% lower for inspections. Separately, an optional preliminary virtual meeting with a planner is billed at the Planning Division's hourly rate of $398/hour with a 30-minute minimum (i.e. $199). These are city permit fees only and exclude school/parkland impact fees, construction taxes, and construction cost. |
| Impact Fees | Two impact fees apply in San José and both are size-gated: school impact fees and parkland impact fees. The city states neither applies to ADUs under 750 sq ft. At 750 sq ft and above, parkland impact fees apply and vary by location (the city publishes a Park Impact Fee map), and school fees are set and collected by the school district(s) for the location, not by the city - the city issues a school fee referral form at submittal. The building permit will not be issued until these are paid. CAUTION for our copy: the city's checklist gates the charge at '750 sf or greater' while Gov. Code 66311.5(c)(1) exempts an ADU of 750 sq ft or less, so at exactly 750 sq ft the city's published wording appears one square foot stricter than the state exemption. Worth hedging rather than restating either side as settled. |
| Plan Check | Standard review process |
| Pre-Approved Plans | Yes - a well-developed Preapproved ADU program, described by the city as the fastest and lowest-cost permit path, supported by a dedicated City review team. 6 preapproved plans from 4 vendors are currently available: Acsiom Designs (749 sq ft, 2bd/2ba); Ca2Homes (499 sq ft 2bd/1ba, 747 sq ft 2bd/2ba); J. Kretschmer Architect (748 sq ft 2bd/1ba, 476 sq ft 1bd/1ba); LiveLarge (795 sq ft 2bd/2ba). Permits may be issued the same day as the scheduled plan review meeting when site-specific documents are accurate and complete (exception: deferred structural submittals, clearances or variances take longer). Eligibility: lot must be zoned residential with an existing single-family home or duplex, and must NOT be in a geohazard, landslide, flood or Wildland-Urban Interface zone. Applicants still submit site-specific plans showing siting, utility connections and setbacks. A further 7 vendors have plans under review (including 800 and 1,000 sq ft options) that are NOT yet eligible for expedited review. |
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Construction Costs [3][4]
Building an ADU in San Jose typically costs $180,000-$400,000 ($250-$450 per sq ft); a garage conversion runs $100,000-$220,000.
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| Average Build Cost | $180,000-$400,000 |
| Cost per Sq Ft | $250-$450 |
| Garage Conversion | $100,000-$220,000 |
| Prefab ADU (Installed) | $130,000-$300,000 |
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
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Rental Income Potential [5][6]
A 2-bedroom ADU in San Jose rents for around $2,500-$3,500/mo, an estimated 5-9% annual return.
| Avg Rent (1 Bedroom) | $2,000-$2,800/mo |
| Avg Rent (2 Bedroom) | $2,500-$3,500/mo |
| Short-Term Rental | Restricted; requires transient occupancy tax registration |
| Est. Annual ROI | 5-9% annual return |
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Recent Law Changes
What's Changed Recently
- SB 543 (Jan 2026): ADU applications deemed approved if city fails to act within 60 days
- AB 1154 (effective Jan 1, 2026): A locality may require owner-occupancy for a JADU only if it shares a bathroom with the primary dwelling; JADUs with their own bathroom are exempt (matching detached ADU rules)
- SB 1211 in effect (2025-2026): Up to 8 detached ADUs allowed on multifamily lots statewide
- AB 1033 opt-in expanding (2026): More cities allowing separate sale of ADUs as condos
Tips for Building an ADU in San Jose
- Silicon Valley rents make ADUs extremely profitable despite high build costs
- Consider a prefab ADU to control costs in a high-cost labor market
- ADU rental income can significantly offset your mortgage in San Jose
- Check with the city's ADU resource center for the latest incentives
ADU Builders in San Jose
Looking for an ADU builder in San Jose? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match San Jose homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Accessory Dwelling Units (ADUs) | City of San José Planning Department — Accessed 2026-02-24
- Preapproved ADUs | City of San José Planning Department — Accessed 2026-02-24
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-02-24
- Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
- HUD Fair Market Rents Government Data — Accessed 2026-02-24
- ADU Ordinance & Updates | City of San José Municipal Code — Accessed 2026-02-24
- California ADU Handbook — HCD Government Data — Accessed 2026-02-24
Frequently Asked Questions
Can I build an ADU in San Jose?
Yes. ADUs are allowed in Any zoning district where the site has a legally-built, permitted main residence - single-family, duplex or multifamily. Not restricted to the named residential districts, so listing R-1/R-2/R-M/R-MH understates where ADUs are allowed. Practical gating is by property condition rather than zone: an active Code Enforcement case must be resolved before plans are accepted, and flood, geohazard/liquefaction/landslide, historic and Wildland-Urban Interface designations add design requirements or clearances rather than prohibiting the ADU. in San Jose. The maximum size for a detached ADU is Depends on which standards track the applicant chooses. CITY Development Standards (SJMC 20.80.175): 1,000 sq ft on lots under 9,000 sq ft; 1,200 sq ft on lots over 9,000 sq ft. STATE Development Standards (SJMC 20.80.176): 800 sq ft on any lot. Minimum size 150 sq ft under either track. The tracks cannot be mixed. Same size table applies on duplex/multifamily lots under the City track.. Owner-occupancy is not required, so you can rent out the ADU.
How much does an ADU cost in San Jose?
ADU construction in San Jose typically costs $180,000-$400,000. Garage conversions run $100,000-$220,000, and prefab ADUs cost $130,000-$300,000.
How much can I rent an ADU for in San Jose?
Average ADU rents in San Jose are $2,000-$2,800/mo for a 1-bedroom and $2,500-$3,500/mo for a 2-bedroom unit.
Do I need parking for an ADU in San Jose?
None. The city states 'None' for parking under both the City and the State development standards, on single-family, duplex and multifamily properties alike. Replacement parking is not required when a garage or carport is converted to an ADU.. Check with San Jose planning department for the latest California ADU parking rules, as many states have relaxed requirements in recent years.
How long does it take to get an ADU permit in San Jose?
The permit review timeline in San Jose is The city's own published figure is that the first round of building review typically takes 20 business days, with complete and accurate plans staying within one or two review cycles. Preapproved-plan projects may receive same-day permit issuance at the scheduled plan review meeting. The 60-day figure in our record is the state ministerial deadline (Gov. Code Chapter 13 / SB 543), not a San José-published processing time, and should not be presented as a city fact. The city flags the missing water-company flow letter as a main cause of delay.. Permit fees: City building permit fees, FY 2026-27 Building and Structure Permits Fee Schedule, effective August 10, 2026. ADU 0-750 sq ft: permit issuance $422, plan review $1,137, inspection $1,732 (total $3,291). ADU 751-1,200 sq ft: permit issuance $633, plan review $1,950, inspection $2,520 (total $5,103). Permit issuance includes addressing assignment for the unit; inspection includes the meter release inspection. Modular fees are 10% lower for plan review and 20% lower for inspections. Separately, an optional preliminary virtual meeting with a planner is billed at the Planning Division's hourly rate of $398/hour with a 30-minute minimum (i.e. $199). These are city permit fees only and exclude school/parkland impact fees, construction taxes, and construction cost.
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