ADU Design & Build · San Jose
ADU Builder in San Jose
San Jose has the biggest lots and one of California's most ADU-friendly cities — we turn that backyard into a $2,500–$4,500/month asset.
San Jose is built for ADUs. The city has some of the largest single-family lots in Santa Clara County, a pre-approved ADU plan program that can shorten design and review, and a building department that processes ADUs every week under the state's 60-day ministerial clock. For homeowners from Almaden to Evergreen to Berryessa, the backyard is the best-priced buildable land they'll ever own.
The math is hard to beat: build a ~$300K asset on land you already have, rent it for $2,500–$4,500 a month in the nation's strongest rental market, and add appraisable value at resale. State law clears the path — compliant units must be approved within 60 days, and units under 750 sq ft are exempt from impact fees.
What separates a smooth San Jose ADU from an 18-month ordeal is execution: a design that fits your lot's setbacks and utilities the first time, a complete submittal (or a pre-approved plan), and a builder who prices the whole job upfront. That's the BARC system, and it starts with a feasibility check on your parcel.
ADU permits in San Jose
San Jose runs ADU permits through the SJePermits portal and offers a pre-approved (standard plan) ADU program that can cut design time and speed review. Detached ADUs up to roughly 1,000–1,200 sq ft are allowed on most single-family lots, and the city holds the state 60-day clock for compliant applications. We confirm whether a pre-approved plan or a custom design is the faster path for your specific lot.
What’s included
Lot Feasibility Check First
Setbacks, utility routing, tree constraints, and buildable envelope on your San Jose parcel — before you spend a dollar.
Pre-Approved or Custom Plans
We run San Jose's standard-plan program when it's faster, or design custom when your lot or goals call for it.
Detached New-Construction ADUs
400–1,200 sq ft backyard homes, studio to 3-bedroom, designed for rental durability.
Garage Conversion ADUs
The fastest, most affordable San Jose path: $125K–$220K for a studio/1BR.
Financing & Fixed Pricing
Cost/rent/payback modeled upfront, in-house loan structuring, and locked construction pricing.
What it costs in San Jose
| Project | Typical Range | Notes |
|---|---|---|
| Garage conversion (≈400 sq ft) | $125K – $220K | Studio or 1BR |
| Detached studio/1BR (400–600 sq ft) | $220K – $330K | $350–$550/sq ft |
| Detached 2BR (750–1,000 sq ft) | $320K – $480K | Best rent-per-dollar for families |
| Attached ADU | $300 – $450 / sq ft | Shares structure; saves foundation cost |
Units under 750 sq ft are exempt from city impact fees statewide. San Jose ADUs typically rent for $2,400–$4,200/month by size.
What we build in San Jose
- Detached ADUs on large Almaden & Evergreen lots
- Pre-approved standard-plan ADUs in Cambrian & Blossom Valley
- Garage-conversion ADUs in Willow Glen & Rose Garden
- 2BR family ADUs in Berryessa & Santa Teresa
- Multigenerational backyard units across East San Jose
ADU Design & Build — full details
Process, scope, and everything our adu design & build service covers Bay Area-wide.
All services in San Jose
Remodels, ADUs, permits, real estate, and financing across San Jose.
San Jose ADU Design & Build FAQs
How much does an ADU cost in San Jose in 2026?+
All-in: garage conversions $125K–$220K; detached 400–600 sq ft units $220K–$330K; detached 2-bedrooms $320K–$480K. Detached new construction runs $350–$550/sq ft. A pre-approved standard plan can trim design cost and time.
Does San Jose have pre-approved ADU plans?+
Yes — San Jose runs a standard (pre-approved) ADU plan program designed to shorten design and plan check. We'll tell you whether a standard plan fits your lot or whether a custom design serves you better, and handle either path end to end.
How big an ADU can I build in San Jose?+
State law guarantees at least 800 sq ft on virtually any single-family lot, and San Jose allows detached units up to roughly 1,000–1,200 sq ft on most parcels. Your feasibility check pins down the exact envelope for your lot, including height and setback limits.
Will San Jose really approve my ADU in 60 days?+
Compliant applications must be approved ministerially — no hearings, no discretionary denial — within 60 days under state law. The city keeps building-code and objective-standard review, which is why a clean, code-annotated submittal (or a pre-approved plan) matters.
What rent will a San Jose ADU earn?+
2026 typical: studios $2,200–$2,800, 1-bedrooms $2,600–$3,400, 2-bedrooms $3,200–$4,500, with the strongest rents in West San Jose and near transit. Most BARC ADUs gross 10–15% of construction cost annually.
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