1000 Sq Ft ADU Cost in San Jose, CA
A 1000 sq ft ADU in San Jose, CA costs roughly $570,000–$979,000 all-in for 2026, including permits, utilities, and soft costs. Adjust the slider to see other sizes.
Cost Breakdown (Mid-Range)
| Category | Amount | Share of Mid Total |
|---|---|---|
| Hard construction (labor + materials) | $625,000 | 85% |
| Soft costs (design, engineering, PM) | $75,000 | 10% |
| Permit and impact fees | $23,000 | 3% |
| Utility hookups | $14,000 | 2% |
| Mid-range total | $737,000 | 100% |
Last updated April 2026.
Building a 1000 Sq Ft ADU in San Jose: What's Specific Here
San Jose runs the largest pre-approved ADU master plan program in the South Bay — using one of the city's pre-approved designs cuts plan check to 4-6 weeks instead of the standard 12-20 week PBCE review. The labor market here is competitive enough that mid-range framing crews are routinely booked out 4-6 months in advance, and impact-fee waivers under AB 681 still apply for builds under 750 sq ft. For a 1000 sq ft build specifically, expect 12-20-week plan review through San Jose Planning, Building and Code Enforcement (PBCE) and a build sequence shaped by the city's mild climate and CA Title 24, CalGreen, San Jose Municipal Code §20.30, master plan program requirements.
What a 1000 Sq Ft ADU Actually Gets You
A 1,000 sq ft 2-bedroom requires the full PBCE plan check in most cases — the master plan catalog thins out at this size. Expect 12-20 week review and full impact fees.
Cost by Build Method
| Build method | Low | Mid | High | Notes |
|---|---|---|---|---|
| Stick-built (custom) | $570,200 | $737,000 | $978,800 | Most common path; highest cost, most layout flexibility |
| Prefab / panelized | $501,776 | $678,040 | $939,648 | 15-25% faster, 5-10% cheaper; limited layout options |
| Modular (factory-built) | $513,180 | $700,150 | $978,800 | 20-30% faster install; needs crane access on site |
Realistic Build Timeline for 1000 Sq Ft in San Jose
| Milestone | Typical duration |
|---|---|
| Design + construction documents | 4-8 weeks |
| San Jose, CA permit submission + review | 12-20 weeks |
| Site prep + foundation | 3-5 weeks |
| Framing + rough-ins (MEP) | 7-10 weeks |
| Finishes + final inspection | 9-13 weeks |
| TOTAL (design → certificate of occupancy) | 35-56 weeks |
Financing a $737,000 1000 sq ft ADU in San Jose, CA
Most San Jose, CA homeowners stack a cash or HELOC down payment with a construction-to-perm loan. Sample scenario for a mid-range 1000 sq ft build:
| Total project cost (mid) | $737,000 |
| 20% down payment (cash or HELOC) | $147,400 |
| Loan principal (80%) | $589,600 |
| Estimated rate (May 2026) | 7.5% (30-year) |
| Estimated monthly payment | $5,153 |
| Estimated rent (1000 sq ft in San Jose, CA) | $2,430–$4,300/mo |
| Break-even rent target | $5,153/mo |
Sample scenario only — your actual rate, term, and rent will vary. Use the loan calculator to plug in your numbers.
San Jose Permit Fee Detail
| Plan check | $1,200–$3,000 |
| Building permit | $2,000–$5,500 |
| Impact fees | Waived (<750 sf) |
| School fees | $3–$5/sf |
| Utility hookups | $3,000–$9,000 |
Questions to Ask San Jose ADU Contractors
Before signing with a contractor for your 1000 sq ft ADU in San Jose, CA, ask:
- How many full 1- and 2-bedroom ADUs have you completed in San Jose in the last 24 months?
- What's your average permit timeline with San Jose Planning, Building and Code Enforcement, and how do you handle plan-check correction cycles?
- Do you handle San Jose master plan program eligibility and labor backlog in-house or sub it out?
- What's specifically included vs. excluded in your turnkey quote — soft costs, utility tap fees, landscaping, driveway repair?
- What's your payment schedule, and what triggers a change order vs. an allowance overrun?
- Can you provide addresses for 2-3 completed San Jose ADU projects I can drive by?
How We Calculate This
These are 2026 all-in market estimates. Hard costs scale linearly with square footage using a low/mid/high per-sq-ft band calibrated to recent build data in each metro. Soft costs (design, engineering, project management) are applied at ~12% of hard costs. Permit and utility hookup fees are set to local base amounts and lightly adjusted for size. For an itemized estimate tied to your lot, finish level, and specific city jurisdiction, use our Cost Estimator.
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Frequently Asked Questions
How much does a 1000 sq ft ADU cost in San Jose, CA?
A 1000 sq ft ADU in San Jose, CA typically costs $570,000–$979,000 all-in for 2026. The mid-range estimate is $737,000, which includes hard construction ($625,000), soft costs ($75,000), permit fees ($23,000), and utility hookups ($14,000).
What is the price per square foot for ADUs in San Jose, CA?
For a 1000 sq ft build in San Jose, CA, expect $570–$979/sq ft all-in. The mid-range is roughly $737/sq ft. Per-sq-ft cost falls slightly at larger sizes because permit and utility fees amortize over more square footage.
How long does a 1000 sq ft ADU take to build in San Jose, CA?
Total timeline runs 35-56 weeks from design start to certificate of occupancy in San Jose, CA. Permits alone take 12-20 weeks through San Jose Planning, Building and Code Enforcement (PBCE), followed by 19+ weeks of construction. Pre-approved plans and prefab paths can shorten the permit phase.
Can I finance a $737,000 ADU in San Jose, CA?
Yes. For a $737,000 mid-range build, common options are construction-to-permanent loans, HELOC, cash-out refinance, or RenoFi. At current ~7.5% rates, a fully-financed build is roughly $5,153/month on a 30-year term. Use the ADU loan calculator to compare products side by side.
What size of ADU is allowed in San Jose, CA?
San Jose, CA permits detached ADUs up to 1200 sq ft on most lots. A 1000 sq ft unit is within the typical limit, so the standard ADU permit path applies.
What rent can I expect from a 1000 sq ft ADU in San Jose, CA?
In San Jose, CA, 1000 sq ft ADUs rent for approximately $2,430–$4,300/month based on 2026 market rents for comparable units. Newer construction with separate parking and a private entrance lands at the high end of that range.
What's the difference between a 1000 sq ft and a 1200 sq ft ADU in San Jose, CA?
A 1000 sq ft San Jose, CA ADU comes in around $737,000 mid-range, while the next bucket up at 1200 sq ft runs about $878,000 — roughly $141,000 more. The bigger size adds a bedroom or larger living area but still falls within the city ADU size cap.
What's the most common mistake when building a 1000 sq ft ADU in San Jose, CA?
Underestimating the san jose master plan program eligibility and labor backlog requirement — many homeowners get bids from contractors who don't price these into the quote, then face change orders mid-build. Always confirm in writing how san jose master plan program eligibility and labor backlog is handled before signing.
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