San Jose, California
San Jose publishes lot-level ADU eligibility data and pre-approved plan sets, and Bay Area rents make it one of the strongest rental-ROI markets for a new unit.
$200K–$280K
All-in build cost
construction, design, permits & fees
$2,800–$3,400
Monthly rent
one-bed comps nearby
2–3 mo
Permit timeline
typical city review window
up to 1,200 sq ft
Typical max size
detached new construction
Estimates from regional cost and rental data — not a quote or a permit decision.
For San Jose ADU builders
Every homeowner searching "ADU cost in San Jose" ends up on a page like this. Our widget gives them the answer for their exact address on your site — and sends you the lead.
FAQ
Most detached ADU projects in San Jose land between $200,000 and $280,000 all-in — construction, design, permits and fees. Garage conversions come in lower; high-end finishes and difficult lots push higher. These are estimates from regional cost data, not a quote.
Local comps put a new one-bedroom ADU in San Jose at roughly $2,800–$3,400 per month, depending on neighborhood, size and finish.
Permit review in San Jose typically runs 2–3 months, helped by pre-approved plan sets, plus design time before you submit. California's 60-day review clock applies to each complete submission — correction rounds are what stretch the calendar in practice.
San Jose publishes lot-level ADU eligibility data and pre-approved plan sets, and Bay Area rents make it one of the strongest rental-ROI markets for a new unit. The fastest way to find out for a specific address is a feasibility check against the city's zoning data — that's exactly what our widget does on builders' websites.