10 Best ADU Builders in San José – 2026

San José homeowners looking to add rental income, house family members, or make better use of an existing lot benefit from California’s streamlined ADU laws and the City’s preapproved plan program. The program is a real advantage, though it is frequently described online in terms that overstate what it does.

For those interested in residential real estate exposure without a construction project, Ark7 offers fractional interests in professionally managed rental-property series, with shares starting as low as $20, subject to offering availability and eligibility.

This guide profiles 10 companies building ADUs across San José and the South Bay, compiled from publicly available company information as of 2026. Pricing, licensing, and review scores change quickly, so verify credentials through the CSLB and confirm current details directly with any company before signing.

Key Takeaways

• San José’s preapproved ADU program can shorten plan review because the standard construction plans have already been reviewed, although each project still requires site-specific review and permitting.
• Prefab construction can shorten the on-site construction phase, but total project time still depends on design, permitting, site preparation, utilities, delivery, and inspections.
• Published contractor estimates for San José ADUs commonly span roughly $150,000 to $400,000 and above, though site-specific bids can fall outside that range.
• ADUs under 750 square feet receive exemptions from certain development impact fees under state law, but utility connection, meter, and capacity charges depend on the serving utility and project circumstances.
• California law generally prohibits local agencies from imposing owner-occupancy requirements on standard ADUs, subject to separate rules applicable to JADUs.
• California Civil Code §4751 limits HOA restrictions that effectively prohibit or unreasonably restrict qualifying ADUs.
• Ark7 offers shares in rental-property offerings starting as low as $20 per share, with monthly cash distributions when applicable.

How This List Was Compiled

This is an editorial selection rather than a scored ranking, and no order of merit is implied below. Most experience figures, project counts, ratings, and pricing are company-reported or drawn from review platforms rather than independently audited, and ratings are current as of August 2026. Where license numbers were publicly available, readers should independently verify current status through the CSLB before contracting, since license status can change at any time.

San José ADU Rules to Understand First

• Preapproved plans: San José operates a preapproved ADU plan program, and the City describes these standardized plans as its fastest and lowest-cost permitting pathway.
• Not a permit: A preapproved master plan is not itself a site-specific permit. Applicants still need a complete site-specific submittal and appointment, and individual properties can carry additional requirements.
• Vendor rosters change: Using a listed vendor does not by itself produce automatic or same-day permit approval, and preapproved-vendor lists are updated over time.
• Zoning: Understanding local zoning across R-1, R-2, and R-M zones matters, so work with builders experienced in San José permitting.
• Setbacks: For many newly constructed ADUs, state law limits required side and rear setbacks to four feet, while conversions and other protected configurations may qualify for different treatment. Fire and life-safety conditions can also affect placement.
• Impact fees: ADUs under 750 square feet receive exemptions from certain development impact fees under state law. Utility connection, meter, and capacity charges are separate and depend on the serving utility, including PG&E for meter requirements.
• HOAs: California Civil Code §4751 limits HOA restrictions that effectively prohibit or unreasonably restrict ADUs or JADUs. Associations may impose reasonable restrictions but cannot effectively prohibit a compliant ADU.

10 ADU Companies Operating in San José for 2026

1. IMKAT Construction (In-House Across Disciplines)

Service Area: San José, based in Pleasanton

Type: Design-Build

Price Range: Company-published $205K to $415K for 300 to 1,200 square feet

Timeline: Company-stated 8 to 14 months

License: Verify the current license number, entity, classifications, status, and disclosures directly through CSLB by legal business name before contracting

IMKAT states that it has completed more than 150 ADUs across California and reports a 4.9-star Google rating from 68 reviews.

What Sets IMKAT Apart:

• In-house design, engineering, permitting, and construction
• RenoFi financing partnership for construction loans
• Models including 1BR, 2BR, 3BR, duplex ADUs, and retirement units
• Free feasibility review consultations
• Vertical integration reducing subcontractor coordination across trades

2. San Jose ADU Solutions (Local Focus)

Service Area: San José, including Willow Glen and Almaden Valley

Type: Design-Build

Price Range: Company-published $150K to $400K

Timeline: Company-stated 8 to 18 months

The company markets itself specifically to San José homeowners and advertises local zoning knowledge along with San José-specific permitting experience.

What Sets It Apart:

• Ten distinct ADU services, including design, engineering, financing, and construction management
• Free site consultations
• Experience with attached, detached, garage conversion, and JADU projects
• Published timeline breakdown of roughly 3 to 6 months for permitting and 5 to 12 months for construction

3. Acton ADU (Long Track Record)

Service Area: South Bay, based in Campbell

Type: Custom Design-Build

License: CA #638333

Timeline: Company-stated 8 to 12 months

Contact: (408) 539-1908, 1257 Dell Ave, Campbell

With more than 30 years of experience, Acton ADU brings substantial longevity to Bay Area ADU construction.

What Sets It Apart:

• Complete in-house design and construction team
• Published San José ADU requirements guidance
• Campbell-based location serving the South Bay
• Acton has previously offered preapproved San José plans; verify current listing against the City’s preapproved-plan list before relying on it

4. D&D Home Remodeling (Customer Feedback)

Service Area: San José and the South Bay

Type: Design-Build

License: CA #1128719

Timeline: Company-stated 6 to 12 months

Rating: 5.0-star Houzz rating with multiple Houzz badges as of August 2026

What Sets It Apart:

• In-house designers and dedicated project managers
• 3D visualization and renderings before construction
• Kitchen, bathroom, ADU, and full-home remodels
• Free estimates, with some published customer reviews praising on-time and on-budget delivery

5. May Construction, Inc. (Long Operating History)

Service Area: San José and the South Bay

Type: Design-Build

Price Range: $100K to $2M

License: CA #524952

Timeline: Company-stated 8 to 15 months

Address: 115 Phelan Avenue, San Jose, CA 95112

May Construction reports more than three decades in business and holds Diamond Certified status. Confirm the specific certification period directly through the Diamond Certified company profile.

What Sets It Apart:

• Best of Houzz awards across multiple years
• Design-build with 3D rendering visualization
• Whole-house remodels, additions, kitchen and bath, and ADUs
• Company-reported high repeat client rate

6. Nestadu (Prefab Specialist)

Service Area: Bay Area including San José

Type: Prefab Manufacturer

Price Range: $150K to $300K typical

Timeline: On-site installation phase is significantly shorter than traditional construction per secondary sources; total project timeline varies

Contact: 888-637-8238, 100 Shoreline Hwy #Suite 386B, Mill Valley, CA 94941

Nestadu has been recognized in SFGATE’s Best of Bay Area reader poll, which reflects reader voting rather than an editorial evaluation.

What Sets It Apart:

• Prefabricated delivery with fully assembled units
• Three sizes: studio, 1BR, and 2BR
• All-electric design with large windows
• Complete kitchen, interior, and exterior finishes

7. Type Five (Architect-Led Model)

Service Area: Bay Area, including San José, based in Berkeley

Type: Architecture-Led Design-Build

Timeline: Company-stated 6 to 10 months

Contact: 510-380-7500, 1336 Channing Way, Suite E, Berkeley, CA 94702

Type Five has been recognized as a finalist in SFGATE’s Best of Bay Area reader poll for its combined architect and general contractor model, which keeps both disciplines in-house.

What Sets It Apart:

• Single-source responsibility with the architect and contractor under one roof
• Cost and timeline established before construction begins
• All-in-one handling of design, permitting, and construction
• A fixed-price structure can reduce budget uncertainty, subject to contract exclusions and approved change orders

8. ASL Remodeling (Premium Finishes)

Service Area: Los Gatos and San José

Type: Design-Build

License: CA #1060310

Timeline: Company-stated 8 to 14 months

Rating: 4.8-star Houzz rating as of August 2026

ASL Remodeling’s portfolio appears oriented toward higher-end residential remodeling and construction, with dual Los Gatos and San José locations.

What Sets It Apart:

• Design-build firm with integrated architecture and construction
• Luxury estate project experience
• Clear upfront estimates
• Custom ADUs and conversions with high-end finishes

9. LiveLarge (Preapproved Plan Option)

Service Area: San José

Type: Prefab with City-Preapproved Design

Price Range: Starting around $412 per square foot

Timeline: Company-stated 4 to 6 months

Contact: info@livelargetech.com, 669-230-1579

LiveLarge has offered a City-preapproved ADU design, which may reduce plan-review work when the project qualifies. Using a listed vendor does not by itself produce automatic or same-day permit approval, since site-specific plans and permit processing are still required.

What Sets It Apart:

• Preapproved 795 square foot, 2BR/2BA ADU model
• Modern prefab construction
• Light steel frame construction
• Fixed pricing inherent to the prefab model

10. Golden View Renovation (Design Technology)

Service Area: San José

Type: Design-Build

Price Range: Company-published garage conversion to 2BR ADU at $220K to $245K

License: CA #1072628

Timeline: Company-stated 6 to 9 months

Address: 1545 Berger Dr, San Jose, CA 95112

Rating: 5.0-star Angi rating as of August 2026

Golden View says it uses an algorithm-assisted design process to analyze customer needs and optimize ADU layouts.

What Sets It Apart:

• Algorithm-assisted design process
• In-house permit processor
• 3D rendering for visual planning
• Published project pricing examples, which are uncommon in this market

How to Choose the Right ADU Builder

• By budget: Published contractor estimates commonly span roughly $150,000 to $400,000 and above. Garage conversions sit at the lower end, with one company publishing $220,000 to $245,000 for a two-bedroom conversion, while custom detached construction reaches the upper end. Prefab pricing at roughly $412 per square foot applies to one preapproved model.
• By timeline: Company-stated timelines range from 4 to 6 months for a prefab preapproved model to 8 to 18 months for custom design-build. Ask whether a quoted schedule begins at contract signing, permit issuance, or groundbreaking.
• By geography: San José proper is served by IMKAT, San Jose ADU Solutions, D&D, May Construction, LiveLarge, and Golden View; the wider South Bay by Acton and ASL; and the Bay Area more broadly by Nestadu and Type Five.
• By construction method: Prefab offers a short on-site phase and fixed pricing, architect-led design-build suits design-sensitive projects, and conversion specialists suit owners working with existing structures.

Questions to Ask Any San José ADU Builder

• What is your California contractor license number, and is it currently active?
• Are you currently listed on the City’s preapproved-plan vendor list?
• How many ADUs have you completed in San José specifically?
• Do you handle permitting in-house or outsource it?
• What is included in your quoted price versus what is additional?
• Can you provide references from recent San José projects?

Financing an ADU in San José

• Home equity options: HELOCs and home equity loans leverage existing home value.
• Construction lending: Construction loans disburse in stages and convert to permanent financing at completion.
• Renovation financing platforms: Some builders partner with platforms that connect borrowers to lenders offering products based on after-renovation value.
• Impact fee exemptions: ADUs under 750 square feet receive exemptions from certain development impact fees under state law.
• Utility charges are separate: Utility connection, meter, and capacity charges depend on the serving utility and project circumstances, including whether a new connection or capacity increase is required. Request a project-specific estimate.
• Budget components to price from your own quotes: Design and architecture, permitting and fees, site preparation and grading, construction per square foot, utility connections, and a contingency allowance.

Comparing ADUs and Fractional Real Estate

Building an ADU can create rental-income potential and may increase a property’s value, though the amount varies substantially by property and market. It also requires substantial upfront capital, months of project management, and ongoing landlord responsibilities.

ADU considerations:

• A San José ADU may generate rental income, but achievable rents vary widely by size, location, and finishes. Build any projection from current comparable listings in your neighborhood.
• Gross rent is not cash flow. Monthly rent multiplied by 12 is gross rental revenue; cash flow is what remains after maintenance, vacancy, insurance, taxes, utilities where applicable, financing, and management.
• Renting an ADU you own carries leasing, maintenance, tenant, insurance, tax, and compliance responsibilities unless those duties are outsourced.
• Any rent-to-cost figure should be stated as an illustrative gross estimate, calculated as annual rent divided by total project cost before expenses, not as a return on investment.
• Capital improvements used in a rental activity are generally capitalized and depreciated after being placed in service, with residential rental real property generally using a 27.5-year recovery period. Component treatment can vary.

How fractional investing compares:

For those who prefer fractional real estate exposure rather than developing and managing an ADU directly, Ark7 is another model to consider:

• Shares in specific rental-property offerings starting as low as $20 per share, subject to offering availability and eligibility
• Monthly cash distributions when applicable, subject to property performance, expenses, reserves, and offering terms
• Professional property selection and management
• Exposure across multiple markets rather than a single local property
• No construction timelines or permitting to manage
• Potential access to secondary trading, subject to holding periods, legal and state restrictions, platform availability, and market liquidity. Liquidity is not guaranteed.
• Ark7 IRA options can hold fractional property investments for potential tax benefits, subject to IRA rules, custodian fees, and individual circumstances

These are speculative securities involving substantial risk, including illiquidity, lack of diversification, and complete loss of capital.

Conclusion

San José’s preapproved plan program is a genuine advantage, but preapproved plans shorten review of the standard construction drawings rather than eliminating site-specific submittal, review, or permitting. Understanding that distinction, and pricing your project from actual bids rather than published ranges, does more for a budget than builder selection alone.

Why San José Stands Out for ADU Projects

• Preapproved plan program: Standardized plans that the City describes as its fastest and lowest-cost permitting pathway.
• State-level protections: California generally prohibits local owner-occupancy requirements on standard ADUs.
• Impact fee exemptions: ADUs under 750 square feet are exempt from certain development impact fees under state law.
• HOA protections: California Civil Code §4751 limits CC&R provisions that effectively prohibit or unreasonably restrict qualifying ADUs.
• Deep builder market: Architect-led firms, prefab manufacturers, and full-service design-build contractors all serve the South Bay.

Investor Tips for San José ADU Projects

Run a CSLB Instant License Check on every contractor by exact legal business name the week you sign, confirming the license class, bond, and any disclosures, rather than relying on a number printed on a website. Verify current preapproved-vendor status directly with the City, since rosters change, and a vendor listing does not produce automatic permit approval. Ask any prefab company to separate on-site installation from the total project duration in writing. When budgeting utilities, treat impact fee exemptions and utility connection charges as separate questions, and get a project-specific estimate from the serving utility. Keep gross rent and cash flow distinct in your model.

For those who prefer residential real estate exposure without a construction project, Ark7 offers shares in rental-property offerings starting at $20, subject to offering availability and eligibility.

Frequently Asked Questions

How much does it cost to build an ADU in San José?

Published contractor estimates commonly span roughly $150,000 to $400,000 and above, though site-specific bids can fall outside that range. ADU cost varies dramatically by square footage, foundation, grading, utilities, design, fire requirements, and site constraints. One company publishes garage conversion to two-bedroom ADU pricing at $220,000 to $245,000, and one preapproved prefab model starts around $412 per square foot. Gather multiple written bids rather than budgeting from a published range.

Does San José’s preapproved plan program mean faster permits?

It can shorten the plan review, because the standard construction plans have already been reviewed. It does not eliminate the rest of the process. A preapproved master plan is not itself a site-specific permit, and applicants still need a complete site-specific submittal and appointment. Individual properties can carry additional requirements, and using a listed vendor does not by itself produce automatic or same-day permit approval.

Can I live in my ADU while renting out my main house?

California law generally prohibits local agencies from imposing owner-occupancy requirements on standard ADUs, subject to separate rules applicable to JADUs. Many homeowners choose to live in the ADU and rent the main house, or the reverse. Confirm the current rules for your specific configuration with San José planning staff, particularly if you are considering a JADU.

How do setback requirements affect my ADU placement options?

For many newly constructed ADUs, state law limits required side and rear setbacks to four feet, while conversions and other protected configurations may qualify for different setback treatment. Fire and life-safety conditions can also affect placement. Verify the current San José Universal Checklist for your specific parcel, and have your builder conduct a site feasibility assessment before design work begins.

Can I build an ADU if I have an HOA?

California Civil Code §4751 limits HOA restrictions that effectively prohibit or unreasonably restrict ADUs or JADUs. HOAs may impose reasonable restrictions consistent with applicable requirements but cannot effectively prohibit a compliant ADU. Review your CC&Rs and raise the project with your HOA before beginning design work.

Neither Ark7 nor Ark7 Properties is a broker-dealer or an investment adviser. Dalmore Group LLC, a registered broker-dealer and member FINRA/SIPC, located at 525 Green Place, Woodmere, NY 11598, is the broker-dealer of record for Ark7, an issuer direct offering. Neither Ark7 nor Dalmore makes recommendations or provides advice about investments, and nothing here should be construed as a recommendation for any security. An investment in an offering constitutes an investment in a particular series and not in Ark7 or any of the underlying assets. Investments on the Ark7 platform are speculative and involve substantial risks, including illiquidity, lack of diversification, and complete loss of capital. Cash distributions are not guaranteed and are subject to property performance, expenses, reserves, and offering terms. Past performance is no guarantee of future results. This article is for informational purposes only.