Engineered for your exact lot, permitted through the City of San Jose. Studios to full 3-bedroom homes, designed around the shape of your property and the house already standing on it.
Custom ADUs from $165,000
Our 1,000 sq ft 3-bedroom model, built for San Jose backyards. See our full Bay Area ADU range or all design-build services.
San Jose gives you two different sets of ADU rules and makes you pick one at application. You cannot take the parts you like from each. That single choice changes how large your ADU can be and where it can sit, and most homeowners have already paid for a design before anyone tells them about it.
San Jose's own development standards. Generally allows the larger unit, with detached ADUs reaching 1,000 or 1,200 sq ft depending on lot size. Comes with the City's own siting, rear yard coverage and building separation rules.
California's baseline ADU law. Generally caps a new attached or detached unit at 800 sq ft with 4-foot side and rear setbacks, but the rules can work better on properties where the City standards make placement difficult.
Neither track is automatically better. On a large flat lot the City Standards usually win on square footage. On a tight lot, an odd shape, or a property where existing structures eat the buildable area, the State Standards can be the only path that gets an ADU approved at all. We evaluate both against your parcel before anything is drawn.
Under San Jose's City Standards, the ceiling on a single-family property depends on how big your lot is. The line sits at 9,000 square feet.
| Standard | San Jose Requirement |
|---|---|
| Detached ADU — lot under 9,000 sq ft | 1,000 sq ft maximum |
| Detached ADU — lot 9,000 sq ft or larger | 1,200 sq ft maximum |
| Attached ADU | 800 sq ft, or 50% of the primary home, not exceeding the detached cap for your lot |
| Lot with an existing JADU | Detached ADU capped at 800 sq ft |
| Duplex or multifamily lot | 800 sq ft maximum |
| Junior ADU (JADU) | 500 sq ft maximum, within the existing single-family home |
| Minimum size | 150 sq ft |
| Rear yard coverage | Cannot exceed 40% of the rear yard or 800 sq ft |
| Side and rear setbacks | 4 feet for detached new construction. Conversions of legally established structures are treated differently. |
| Parking | None required |
| Fire sprinklers | Not required if the primary residence does not have them |
| Units per property | One ADU and one JADU |
Standards published by the City of San Jose — Accessory Dwelling Units. Requirements change and depend on your zoning district and property conditions, so we confirm what applies to your specific parcel before design begins.
The two that catch peopleThe rear yard rule can cap you below the size limit. Structures cannot cover more than 40% of the rear yard or 800 square feet. On a smaller San Jose lot that math runs out well before you reach 1,000 square feet, and it is decided by your lot, not your floor plan.
A JADU changes the ceiling. If the property already has a junior ADU inside the house, the detached ADU you can add drops to 800 square feet. Worth knowing before you convert that spare room.
This is where an ADU builder who pulls permits in San Jose regularly saves you real money. Rulebook choice, lot size, rear yard coverage, setbacks and the house already standing on the property all interact, and a design that ignores any one of them gets rejected at plan check. We run the evaluation before anything is drawn, so the first set submitted is the set built to be approved.
Every custom ADU model we build comes in two exterior styles with the identical floor plan inside. Which one belongs on your property usually comes down to your existing home. A Willow Glen craftsman and an Almaden ranch call for very different treatments, and the ADU should read as part of the property rather than something dropped behind it.
Modern Farmhouse
Pitched rooflines, board siding, warmer detailing
Modern Contemporary
Clean lines, flat planes, larger glazing
We walk your lot, confirm which rule set gives you the better ADU, and tell you honestly which models fit before you spend a dollar on design. Book a free consultation or see our full design-build services.
Six floor plans, each one a starting point we customize to your lot. Every model comes in Modern or Farmhouse. Every price below is a real starting number, not a teaser rate that climbs once you are committed.
Studio · 1 Bath
$165,000
Starting from
Our most efficient unit, and the fastest route to rental income on a tight San Jose lot. Small enough that rear yard coverage is rarely the limiting factor.
Floor Plan & Details
1 Bed · 1 Bath
$235,000
Starting from
A true one-bedroom with French doors to the yard. Compact enough to work on almost any single-family parcel in San Jose without fighting the rear yard coverage rule.
Floor Plan & Details
2 Bed · 1 Bath
$300,000
Starting from
Two bedrooms without going full size. Stays under 750 sq ft, so it clears the local impact fee exemption while still renting as a two-bedroom.
Floor Plan & Details
2 Bed · 2 Bath
$372,000
Starting from
Two bedrooms, two full baths, one ensuite. Enough room to live in long term rather than pass through. A favorite for multigenerational households, and it works under either rule set.
Floor Plan & Details
3 Bed · 2 Bath
$450,000
Starting from
The detached ceiling under San Jose's City Standards on a lot below 9,000 sq ft. This one lives like a house, not an add-on.
Floor Plan & Details
3 Bed · 2 Bath
$540,000
Starting from
Our largest model, with a primary suite and private patio. In San Jose this size is permitted on lots of 9,000 sq ft or more under the City Standards.
Floor Plan & DetailsWant a size that is not on this list? We draw it custom. These plans exist because they cover what most San Jose lots need, not because they are the only thing we build. For the full regional picture, see our ADU builder Bay Area page and the complete ADU cost breakdown.
Straight talk on pricing. Our starting-from numbers cover far more than the build itself, and everything outside them is named here, before you sign, rather than discovered in month four.
Covered by the number you were quoted
Named up front, never a surprise
You are never on your own for finishesThrough our showroom partners across the Bay Area, we help you select every finish material, flooring, cabinets, countertops, tile, and fixtures, and have it delivered directly to your project on our construction schedule. All the choice, none of the logistics.
Every item above is broken out in a line-item proposal before you sign anything. You will know exactly what you are paying for and where it goes, in writing, before a single wall goes up.
Most San Jose homeowners financing an ADU hit the same wall: a standard home equity loan lends against what your property is worth today, not what it will be worth with a second permitted dwelling on it. That gap is what stops good projects before they start.
We partner with RenoFi, which lends against your home's after-renovation value, so your borrowing power reflects the finished property rather than the current one. It works across everything we build, from a San Jose kitchen remodel to a bathroom remodel to a home addition or a custom ADU.
Check If You QualifyBuilding more than one space? See our kitchen remodel, bathroom remodel and whole home remodeling pages for San Jose, or browse the full range of design-build services.
Permit and impact fees go directly to the City of San Jose and the applicable districts. We never mark them up and we never take a cut. Most builders quote a vague Bay Area range. Here are the City's actual published numbers.
Most contractor sites give you a range. San Jose publishes the actual numbers, and your ADU's size determines them, not a percentage of your construction cost.
| ADU Size | Permit Issuance | Plan Review | Inspection |
|---|---|---|---|
| 0–750 sq ft | $422 | $1,137 | $1,732 |
| 751–1,200 sq ft | $633 | $1,950 | $2,520 |
| Building Division base total | $3,291 for 0–750 sq ft · $5,103 for 751–1,200 sq ft | ||
Base fees from the City of San Jose Building and Structure Permits Fee Schedule, FY 2026–27, effective August 10, 2026. These are Building Division base charges and are subject to hourly minimums and actual time where applicable. Fire, Public Works, development taxes, school district, parkland and other project-specific charges may apply separately.
Two details worth knowing, because they are easy to miss: the ADU permit issuance fee includes your address assignment, and the inspection fee includes the meter release inspection. Both are things homeowners often assume will show up as separate line items later.
San Jose requires a letter from your water provider showing flow and pressure at the hydrant closest to the property, submitted with the building permit application. The City specifically tells applicants to request it early, because a missing letter may delay permit issuance.
If the results do not meet 1,000 gpm at 20 psi, Fire staff reviews them and determines whether additional fire-safety measures are required. We request the letter the moment design starts rather than when the rest of the package is ready, so a short result is something we plan around in week one instead of discovering at submittal.
The 750 square foot rule applies to local impact fees charged by the City, special districts and water corporations. School impact fees are separate and are set by the school district serving your property, not by San Jose.
This is where most contractor pages get it wrong. Under California's current 2026 ADU guidance, school districts may charge school impact fees on ADUs larger than 500 square feet. Because San Jose spans multiple school districts and their requirements vary, we confirm the applicable district and its current fee before the project budget is finalized.
Depending on the property and project, Parkland, Public Works, Fire, development tax and other agency charges may also apply before permit issuance.
San Jose does not have one all-in ADU permit price. The Building Division charges above are structured by ADU size, while Fire, Public Works, development taxes, parkland, school district and other project-specific charges are assessed separately depending on your property.
That is why we never fold permits into a headline price. You would have no way to tell what you were actually paying for. We use the current City fee schedule and your property conditions to build a project-specific permit budget during the free consultation. Final agency fees are set by the City and the applicable districts. For how San Jose compares to the rest of the region, see our ADU builder Bay Area page and the Bay Area ADU cost guide.
This is the whole reason most San Jose homeowners build. An ADU is not extra space — it is an income-producing asset on land you already own, in one of the strongest rental markets in the country.
These are planning ranges, not guarantees. A detached ADU typically rents below a comparable San Jose apartment — no gym, no pool, no parking structure, and a shared lot — while still commanding a premium in the neighborhoods people actually want to live in. Actual rent depends on your unit size, finish level, parking, privacy, and whether you are in Willow Glen or out past Berryessa. We pull live comps for your specific address during the consultation.
Ranges set below current San Jose market rents reported by Zumper, Rentometer and RentCafe as of July 2026, because a backyard ADU is not a full-amenity apartment building. Rental markets move; we verify against live listings for your address.
Read that honestly. That figure is gross yield on the build cost alone. It does not account for permit fees, financing costs, property tax on the new square footage, vacancy, or maintenance — all of which are real. Net returns land meaningfully lower. What the number does show is the scale: roughly $44,000 a year against land you already own, which is why an ADU competes with almost any other use of the same capital.
A legal, inspected ADU adds documented living area to your property. That is square footage an appraiser counts and a buyer pays for. Unpermitted work does the opposite — it can block a sale outright.
Monthly rent while you hold it, and a higher number when you sell it. Most improvements give you one or the other. An ADU is among the few that reliably gives you both in a market like San Jose.
Not every homeowner builds for a tenant. Plenty of the ADUs we build in San Jose house a parent who wants to stay close, or an adult child priced out of the local market. The financial case still holds — you are housing family at zero rent instead of paying Santa Clara County rates elsewhere, and the property value is there either way.
Every model we build is delivered turnkey: design, engineering, permits, construction, and a professional final clean, handed over ready to occupy or list. You are not left coordinating a punch list between four trades to get a certificate of occupancy.
For Investors & Real Estate Professionals
Plenty of the San Jose ADUs we build are investments first. If you are buying a property and need to know what it will actually support before you close, or planning more than one build, we handle that differently than a single-family project — lot feasibility reviewed before you commit, written scope and cost you can put in front of a lender, and turnkey delivery ready to rent on handover.
Agents working a client through the same question are welcome to call us in early. A real answer on what a lot allows is worth more to your buyer than a guess.
San Jose is genuinely one of the faster big cities in California for ADU permitting. That is not marketing, it is what the City publishes. What decides your timeline is not the City's speed. It is how many times your plan set has to go back.
California law requires a permitting agency to approve or deny a completed ADU application within 60 days. The City also has 30 days to tell you the application is incomplete, and if it does not, the application is deemed complete. Those are real protections and they are worth knowing.
But the clock only starts when the submittal is complete. Miss the hydrant flow letter, the Title 24 calculations, or an owner signature, and there is no clock at all. That is the part most contractor sites leave out.
San Jose's own published figure is 20 business days for the first round of building review, unless your plan needs additional review. The City also says accurate, complete plans help keep a project within one or two review cycles. Two cycles is fast. Five is not, and five is entirely self-inflicted.
Before anything is drawn we walk the property, confirm lot size against the 9,000 sq ft line, check rear yard coverage, and compare what the City Standards and State Standards each allow on your parcel. This is also when we request the water provider's hydrant flow letter, because it is the one document that can sit and wait while everything else is ready.
3D design, full blueprints and elevations, Title 24 energy calculations, CALGreen documentation, structural engineering and property survey. Everything is dimensioned against the rule set we selected in step one, so the drawings, the calculations and the site plan all say the same thing when they reach a reviewer.
Submitted electronically through the City's plan review system. First round runs 20 business days per the City's published figure. Comments come back, we respond and resubmit. Building, Fire and Public Works each review. A clean set clears in one or two cycles. This is the part we are paid to get right the first time.
Privacy fencing, portable restroom, dumpster, and a walk of the property with you first to see what landscaping is worth saving. Utility coordination runs in parallel, including the separate PG&E meter that PG&E now requires for ADUs.
Foundation through finishes, with a City Building Inspector signing off at every stage. If your project requires fire sprinklers or Public Works work, those inspections are run separately by each department. Your dedicated project manager coordinates all of it.
The building permit is finaled and occupancy granted once construction is complete and the City's final inspection passes. Your ADU's address assignment and meter release inspection are both already covered in the permit fees. We bring in a professional crew for a full clean inside and out, then walk the finished ADU with you.
From first consultation to keys, for a new construction ADU in San Jose. A conversion of existing space runs shorter. This is our own estimate built on the City's published review times and our construction schedules, not an optimistic number designed to win the job.
First-round review time and plan cycle guidance published by the City of San Jose ADU FAQs. The 60-day approval requirement and 30-day completeness rule are set in California Government Code §66317, which replaced the former §65852.2. Actual timelines vary with project scope, site conditions, and how many review cycles an application requires.
The variable you control is the number of review cycles. San Jose tells you plainly that accurate, complete plans keep a project within one or two. A set drawn by someone unfamiliar with this city routinely takes four or five, and each additional cycle is weeks you do not get back.
The other variable is the paperwork that has nothing to do with drawings. The hydrant flow letter, the Title 24 calculations, the CALGreen documentation, the owner declarations. San Jose will not process an incomplete package, which means a missing letter does not slow your review down, it stops it from starting. We request those in week one rather than week ten.
That is why the feasibility walk and the rulebook decision happen before we draw anything, and why our architect and engineer visit your property in person rather than working from a satellite image. Getting through plan check quickly is not luck. It is the whole job. See the full ADU process across the Bay Area or our design-build services.
Prefab is a real option and it suits some properties. It does not suit most San Jose lots, and the reasons are specific rather than a matter of taste. Here is the honest comparison.
| Prefab / Modular ADU | Custom Built On-Site | |
|---|---|---|
| How it is made | Built in a factory to a fixed catalog plan, trucked in, and craned onto a prepared foundation | Designed for your parcel, then framed and finished on your property by one team |
| Fitting your lot | The plan is fixed. Your lot has to accommodate the unit, including crane access and a clear delivery path | The design responds to your setbacks, rear yard coverage, slope, mature trees, and where your existing home sits |
| Matching your house | Limited exterior options within the manufacturer's catalog | Modern or Farmhouse elevations, finishes chosen to read as part of the property |
| San Jose size limits | You choose from what the factory offers and hope a size fits the cap that applies to your lot | Drawn to the ceiling your parcel actually allows, 1,000 or 1,200 sq ft, using the square footage rather than leaving it on the table |
| Choosing the rule set | A catalog unit is what it is. If it does not work under one rule set, that is the end of the conversation | We compare City and State Standards against your parcel and design under whichever one builds you the better ADU |
| Site work | Foundation, utilities, grading, and permits are usually yours to arrange separately | Design, engineering, permits, site work, and construction under one contract |
| Crane and access | Needs street width, overhead clearance, and staging room. Many older San Jose lots cannot take delivery | No crane, no delivery constraint. Materials come in through the side yard |
| Changes mid-project | Effectively locked once the unit is in production | Possible, priced in writing before we proceed, with the cost in days and dollars stated up front |
| Who is accountable | Manufacturer, site contractor, and permit expediter are often three separate parties | One licensed general contractor, one project manager, one point of accountability |
| Where it is faster | Factory build runs parallel to site prep, which can compress the construction window | Plan check is the real variable in San Jose, and a complete first submittal saves more time than a factory ever will |
On a flat, wide, easily accessed lot where the homeowner wants a standard studio and does not care whether it matches the main house, prefab can be quicker and occasionally cheaper. If that describes your property and your goals, it is a reasonable choice and we will tell you so. What we will not do is pretend a factory unit solves the part of a San Jose ADU that actually takes time, which is getting a complete, coordinated package through the City's plan check.
Two rule sets, and you pick one. San Jose makes you choose between the City Standards and the State Standards at application, and you cannot mix them. That decision changes your size cap, your setbacks and your siting options. A catalog unit was designed without knowing your parcel, which means nobody made that decision on your behalf and it may not work under either track.
Rear yard coverage caps you before the size limit does. Structures cannot cover more than 40 percent of the rear yard or 800 square feet. On plenty of San Jose lots that math runs out well before you reach the 1,000 sq ft ceiling, and it is decided by the shape of your property rather than by the model you picked from a website.
The housing stock varies enormously. A Willow Glen craftsman, an Almaden ranch and a newer Berryessa build each call for a different treatment. An ADU that reads as a shipping container behind a period home costs you at resale, whatever it saved you at purchase.
We build custom because on the lots we actually work, in San Jose and across the South Bay, it produces a better result for close to the same money. Every one of our six ADU models is a starting point rather than a fixed product, and every one gets adjusted to the property it is going on.
A boutique, owner-led design-build firm headquartered in San Jose. You work directly with the people responsible for your ADU, from the first walk of your lot to the day we hand you the keys.
You deal directly with the owners — the same people from your first conversation to your final walkthrough. No handoff to a crew you have never met, no salesperson who disappears once the contract is signed.
One point of contact who knows your project inside out, from first sketch to final punch list. No call centers, no getting bounced between a scheduler and a foreman, no explaining your job to a stranger every time you call.
Architect, engineer, permit submittal, and construction all in-house. When something needs solving there is nobody to point at — and nobody charging you twice for a redesign that came back over budget.
We design and build on your lot, around your existing home. Every model is a starting point adjusted to your parcel, your rear yard coverage, and the size cap that actually applies to you — not a factory box dropped in the yard.
San Jose is where we are based and where we pull the most permits. The two rule sets, the 9,000 sq ft lot line, the 20-day review cycle, the hydrant flow letter, the current fee schedule. The reason those numbers are published on this page is that we work with them.
A detailed proposal before you sign anything, with every item priced. The only thing that moves the number is a change you request or something genuinely unexpected behind a wall — and either way you get a written change order first.
Your payment schedule follows completed construction, not our cash flow. California law caps what a contractor can collect before work begins and we follow it. Any builder asking for a large percentage up front is telling you something.
Professional clean inside and out, final City inspection passed, occupancy granted, then we walk the finished ADU with you. You get keys to a completed home — not a punch list to chase across four trades.
Real reviews from Bay Area homeowners, pulled live. Read them yourself rather than taking a number on a contractor's website at face value.
A fully licensed California general contractor. We are happy to provide our license and insurance documentation before you sign anything, and frankly you should ask that of every contractor you are considering. An ADU is permanent construction on your property — the paperwork matters as much as the craftsmanship.
See the work rather than the claims. Our completed projects include ADUs, kitchens, bathrooms, and whole-home renovations across San Jose and the South Bay, and our homeowner testimonials come from the people who lived through the build. If you want to know who you would actually be working with, start with our story.
The questions San Jose homeowners actually ask us before they hire anyone, answered the way we would answer them on your property.
Our starting prices run from $165,000 for a 350 sq ft studio to $540,000 for a 1,200 sq ft three-bedroom, delivered turnkey. Those numbers include labor, rough materials, 3D design, full blueprints, Title 24, structural engineering, property survey and utility trenching up to 20 feet.
Priced separately, and named before you sign: City permit and impact fees, finish materials, appliances, soil report if your lot needs one, special inspections, and any site-specific work like grading. What moves a price after that is a change you request or something genuinely unexpected behind a wall, and either way you get a written change order with a number before we proceed.
Roughly 8 to 12 months for a new construction ADU in San Jose. That breaks down as one to two weeks of feasibility, six to eight weeks of design and engineering, one to three months in plan check, four to five months of construction, and a couple of weeks for final inspection and handover.
A conversion of existing space runs shorter. The variable that moves the number most is how many plan review cycles your submittal takes, which is why we do the feasibility work before anything is drawn.
Yes, and almost everyone does. A detached ADU is built in your yard rather than inside your home, so your kitchen, bathrooms and bedrooms stay in use throughout.
What you will notice is site access, noise during working hours, and a portion of your yard fenced off for materials and equipment. We walk the property with you before anything starts to agree where the fencing goes, what landscaping is worth protecting, and how crews will reach the build without running through your living space. Brief utility interruptions happen when we tie in water, sewer and electrical, and those are scheduled with you in advance.
All of it. We build ADUs in Willow Glen, Almaden Valley, Rose Garden, Cambrian Park, Evergreen, Berryessa, Alum Rock, Santa Teresa, Naglee Park, Japantown, Downtown, North San Jose, Blossom Valley, Silver Creek, Alviso and the neighborhoods in between.
Where you are matters more than most homeowners expect. A Willow Glen craftsman on a deep narrow lot, an Almaden ranch with room to spare, and a newer Evergreen build each present a different problem, and lot size decides whether your detached ceiling is 1,000 or 1,200 square feet. That is the first thing we check when we walk your property.
Payments are tied to completed construction milestones, not to our cash flow. You pay for work that has been done and that you can see.
California law caps what a contractor can collect before work begins, and we follow it. If a builder is asking you for a large percentage of the contract up front, that tells you something about how they run their business, and it is worth asking why.
No. Our architect and structural engineer are part of the team, and design, engineering, permitting and construction all run through one contract.
The reason that matters is the redesign loop. Hire an architect independently and you can end up with a beautiful set of drawings that prices well over budget, or one that runs into a lot constraint nobody checked, and then you pay a second time to fix it. When the people pricing and building the project are in the room while it is being designed, that does not happen.
Yes. California permanently eliminated owner-occupancy requirements for ADUs, so you can rent the ADU without living on the property, and you can rent both the primary home and the ADU.
Rentals must be for terms longer than 30 days, which rules out short-term letting. Check your own deed and any HOA covenants as well, because a private restriction can limit what zoning permits.
Four things separate builders who finish cleanly from builders who do not.
Verify the license. Check it free at cslb.ca.gov and confirm the number matches the company name on your contract. Ask what happens before anything is drawn. Anyone who quotes a design without walking the property and checking your lot against both rule sets is guessing. Ask for a line-item proposal. A single number with no breakdown is a number that can move. Ask about the payment schedule. It should follow completed work.
Then ask each builder how many ADU permits they have pulled in San Jose specifically. Plenty of firms run location pages for cities they rarely work in. The City's requirements are not difficult once you know them, but learning them on your project is expensive.
California Bay Builders & Remodeling is a licensed, owner-led design-build general contractor (CSLB #1130783) headquartered in San Jose. Design, structural engineering, permit submittal and construction all run through one team.
We start by walking your property and comparing what San Jose's City Standards and State Standards each allow on your specific parcel, because that decision changes your size cap and your siting before a single line is drawn. Then we handle the full package the City requires, including the documents that most commonly hold projects up, so your submittal goes in complete and accurate the first time.
We hand off turnkey: final inspection passed, permit closed, site professionally cleaned, keys in your hand. Five-star rated on Houzz and Google, three-time Best of Houzz Service award winner, verified NKBA member, BBB accredited, licensed, bonded and insured.
If you have the lot, we can build the ADU. Designed around your property, permitted through the City of San Jose, and delivered turnkey by one owner-led team.
The consultation is free and there is no obligation. We walk your lot, compare what the City Standards and State Standards each allow on your parcel, and tell you honestly what it will cost before you invest a dollar in design.
California Bay Builders & Remodeling
2150 N 1st Street, Suite 400, San Jose, CA 95131
(800) 209-0051 · info@californiabaybuildersandremodeling.com
Licensed, Bonded & Insured · CSLB #1130783
San Jose Neighborhoods We Build In
Willow Glen · Almaden Valley · Rose Garden · Cambrian Park · Evergreen · Berryessa · Alum Rock · Santa Teresa · Naglee Park · Japantown · Downtown San Jose · North San Jose · Blossom Valley · Silver Creek · Communications Hill · Alviso · West San Jose · East San Jose
Also Serving San Jose
Beyond custom ADUs, we handle kitchen remodels, bathroom remodels, room additions and whole home renovations across San Jose and the South Bay. See our full range of design-build services or browse the Bay Area ADU program.
Based in San Jose and building accessory dwelling units across the Bay Area. If your city has its own ADU page, you can open it below for local permit information, project details, and what to expect.
Do not see your city linked yet? We may still serve your area. Tell us where the property is and we will let you know what your city requires.
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