Prefab ADUs in San Jose
San Jose builds more ADUs than any other Bay Area city — and has some of the highest rents in California. We deliver an all-in prefab ADU from our factory 60 miles away — permits, foundation, delivery and installation included — at one fixed price.
Free lot check · zoning, fire & hydrant access · reply with a fixed price
Licensed builder · Our own factory in Lathrop, CA
Real homes we build, start to finish
Quick answer
ADUs in San Jose — key facts for 2026
Most San Jose homeowners can add a detached ADU of up to 1,000 sq ft. ADUs up to 750 sq ft pay no school or park fees, there are no parking requirements, and Bay Modular delivers a factory-built ADU all-in for $124,900–$271,900 — the same price anywhere in California.
- Can I build an ADU in San Jose?
- Yes, on most lots with a house. San José allows a detached ADU up to 1,000 sq ft (1,200 sq ft on lots over 9,000 sq ft) with 4-ft side and rear setbacks.
- How long does a San Jose ADU permit take?
- The first building review typically takes about 20 business days, and state law requires a decision on a complete application within 60 days.
- What fees does San Jose charge?
- No school or park fees for ADUs up to 750 sq ft. Larger ADUs pay them — San José Unified charges $5.38 per sq ft.
- How much does a prefab ADU cost in San Jose?
- Bay Modular: $124,900–$271,900 all-in, the same price as anywhere in California, permits and installation included.
- Can I sell an ADU separately in San Jose?
- Yes. San José allows ADUs to become condos (Ord. 31095); the first sale in California, a 749 sq ft 2-bedroom, closed for $530,000 in 2026.
- What does an ADU rent for in San Jose?
- Average asking rent in San José was $3,563 a month in August 2026 (Zillow); HUD's 2027 fair rent for a 1-bedroom is $2,778.
Sources: HCD APR 2025, San José ADU Universal Checklist (Bulletin #210, Sep 2026), SJMC 20.80, Zillow ZORI Aug 2026. Last reviewed October 2026.
San Jose in numbers
San Jose homeowners keep building ADUs
About 500 ADU permits a year since 2023 — steady demand, and about one in five of all new homes in the city.
ADU permits issued in the City of San José
Source: California HCD Annual Progress Report data (Table A2), City of San José, permits issued per year. Percent = ADUs among all housing units permitted in the city that year.
average San Jose asking rent since January 2021 ($2,684 → $3,563)
Zillow Observed Rent Index, City of San José, Aug 2026Bay Area city for ADU permits in 2025 — and #4 in all of California
HCD APR data, 2025Can I build in San Jose?
Most San Jose lots with a house can add an ADU
San José follows all state ADU laws and lets you choose City or State standards. Here is what matters for most homeowners:
City standards allow a detached ADU up to 1,000 sq ft — 1,200 sq ft on lots over 9,000 sq ft. All our models fit.
4 ft from side and rear lot lines; up to 18 ft for one story under City standards (16 ft under State standards).
No parking required and no limit on bedrooms or baths. One ADU plus one JADU per single-family lot.
The ADU must be within 150 ft of the curb by a clear path and near a hydrant with enough flow — a common delay we check first.
Wildland-urban interface, landslide and flood-zone lots have extra reviews and can't use the city's preapproved-plan lane.
San José lets ADUs become condos and be sold on their own (AB 1033, Ord. 31095) — rare in California.
Based on San José ADU Universal Checklist (Bulletin #210, updated Sep 16, 2026), SJMC 20.80.175–176 and the HCD ADU Handbook (2026). Not legal advice — rules depend on your exact lot. More in our San Jose ADU guide.
New in 2027: under AB 956 (Chapter 791, Statutes of 2026), from January 1, 2027 state law lets you build two detached ADUs on a lot with a single-family home, and HOA rules can’t block an ADU on a lot zoned to allow one.
Costs & fees in San Jose
What an ADU costs in San Jose
Same all-in price as anywhere in California. Every one of our models is 750 sq ft or less, so none of them pays San José school or park fees.
| Model | All-in price | School fee | Park fee |
|---|---|---|---|
| Backyard Studio120 sq ft · home office or guest studio, not a rentable ADU | $75,900 | $0 | $0 |
| Small Studio256 sq ft | $124,900 | $0 | $0 |
| Large Studio ADU320 sq ft | $154,900 | $0 | $0 |
| 1 Bedroom ADU480 sq ft | $214,900 | $0 | $0 |
| 2 Bedroom ADU640 sq ft | $271,900 | $0 | $0 |
Sources: San José ADU Universal Checklist (Bulletin #210, Sep 2026) and ADU FAQs; San José Unified developer fee page (Oct 2026); Gov. Code §66311.5. Launch pricing runs through December 31, 2026. Comparison is general — every project differs.
Renting in San Jose
Renting out an ADU in San Jose
average asking rent for all homes in San José — up 33% since 2021. HUD's 2027 fair rent for a 1-bedroom here is $2,778.
Zillow Observed Rent Index, City of San José, Aug 2026 · HUD FY2027 FMR ADU for rental incomeSan José bans short-term rentals in ADUs (SJMC 20.80.160) and requires stays of 30+ days — plan on long-term tenants.
San José's Apartment Rent Ordinance covers 3+ unit buildings from before 1979 and explicitly exempts ADUs.
A new ADU is exempt from California's statewide rent cap (AB 1482) for 15 years after its certificate of occupancy.
Same money, other options
Yearly income per dollar, before taxes and costs. An ADU wins because you already own the land. Full comparison →
Sources: SJMC 20.80.160; San José Housing Department rent stabilization page (Oct 2026); Civil Code §1947.12. Comparison: HUD FY2027 2-bedroom Fair Market Rent, San Jose-Sunnyvale-Santa Clara area ($3,272) × 12 ÷ $271,900; U.S. Treasury (Oct 6, 2026); FTSE Nareit (Sep 2026); Zillow ZORI ÷ ZHVI, San Jose metro (Aug 2026); FDIC (Sep 2026). Not legal or investment advice.
Permits in San Jose
How your San Jose permit works — we handle it
Free lot check
Zoning, fire & flood maps, setbacks, hydrant flow, sewer and power for your San Jose address.
Plans & submittal
Our HCD-approved plans plus your site plan, submitted online to San José Building.
City review
First building review typically takes about 20 business days. We answer corrections for you.
Decision in 60 days
State law requires a decision on a complete application within 60 days. Your ADU is built in our factory meanwhile.
Install & move in
Delivered from Lathrop — about 60 miles away — installed in about a week, inspected, then your Certificate of Occupancy.
Based on San José ADU FAQs and plan-review pages (Oct 2026) and Gov. Code §66317. San José also runs a Preapproved ADU program for vetted vendors with same-day permits on eligible lots.
Why now
Start your San Jose ADU with zero risk
Lock in launch pricing, see exactly what you get, and only decide once you have a fixed price for your lot.
All-in from $75,900 — everything included
- Backyard Studio (home office)$75,900All-in · fixed in writing
- Small Studio$124,900All-in · fixed in writing
- Large Studio ADU$154,900All-in · fixed in writing
- 1 Bedroom ADU$214,900All-in · fixed in writing
- 2 Bedroom ADU$271,900All-in · fixed in writing
Zero-risk start
- Free lot check & quoteNo obligation, no credit card.
- One fixed all-in priceDesign, permits, delivery and install — one number.
- HCD-approved plansState approval #1585366, financed and appraised like a home.
- 2-year warrantyOn materials and workmanship.
Visit our factory in Lathrop, CA and walk through a finished ADU.
San Jose ADU questions
Read the full San Jose ADU guide, see all of California, or call (209) 214-6845.
Can I build an ADU on my lot in San Jose?
Most San José lots with a house can add one ADU plus one JADU. City standards allow a detached ADU up to 1,000 sq ft (1,200 sq ft on lots over 9,000 sq ft) with 4-foot side and rear setbacks. Hillside, fire and flood lots have extra reviews — we check your address for free.
How much does an ADU cost in San Jose?
Our all-in prices are the same as anywhere in California: from $124,900 for a Small Studio to $271,900 for a 2 Bedroom ADU, with launch pricing through December 31, 2026. All our models are 750 sq ft or less, so they pay no San José school or park fees.
How long does an ADU permit take in San Jose?
San José's first building review typically takes about 20 business days, and state law requires a decision on a complete application within 60 days. Your ADU is built in our factory at the same time, so most projects take 4–6 months from signing to keys.
Do I need parking for an ADU in San Jose?
No. San José requires no parking for ADUs.
Can I rent my San Jose ADU on Airbnb?
No. San José does not allow short-term rentals in ADUs; stays must be 30 days or longer.
Is a new ADU in San Jose under rent control?
No. San José's Apartment Rent Ordinance exempts ADUs, and a new ADU is exempt from the statewide rent cap for 15 years.
Can I sell my ADU separately in San Jose?
Yes. San José adopted AB 1033 (Ordinance 31095), so an ADU can be split off as a condo and sold. California's first ADU condo sale, a 749 sq ft 2-bedroom in San José, closed for $530,000 in 2026.
Is an ADU a better investment than a rental property in San Jose?
For most homeowners with room on their lot, yes: you don't buy land. A 2 Bedroom ADU at HUD's 2027 fair rent for a 2-bedroom ($3,272) earns about 14.5% a year on its price before costs, vs. about 3% for a typical San Jose-area rental home (Zillow, Aug 2026). Not investment advice.
Free · no obligation
Can you build an ADU on your San Jose lot?
Send your San Jose address. We'll check zoning, fire and flood maps, hydrant access and utilities, and send a fixed all-in price — permits included.
HCD-approved plans (#1585366) · 2-year warranty · factory in Lathrop, CA
Sources: California HCD Annual Progress Report data, Table A2 (City of San José, 2021–2025, updated Oct 2026); Zillow Observed Rent Index, City of San José (Aug 2026); HUD FY2027 Fair Market Rents; San José ADU Universal Checklist (Bulletin #210, Sep 16, 2026), ADU FAQs, Preapproved ADU and ADU condominium pages; SJMC 20.80; San José Unified developer fees; San José Housing Department; Civil Code §1947.12; HCD ADU Handbook (2026). General information, not legal or investment advice. Updated October 2026.