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If you have questions about the ADU permitting process, please reach out to our ADU
Ally at the Permit Center:

ADU Ally

Preapproved ADUs

Are you looking for a faster, lower-cost way to an accessory dwelling unit (ADU)? 

ADU designers/builders who offer standard construction plan layouts that are preapproved can offer their customers the City's fastest, lowest-cost permit process. Jump to the Preapproved Vendors section to see vendors who are offering preapproved plans in San José. 

This preapproval program applies only to detached ADUs. All preapproved plans are still subject to any site concerns.  

For vendors seeking to obtain approval of master construction plans, see the next section.

For homeowners using preapproved plans, see the Homeowners section below.

VENDORS:  How do I obtain a master plan approval?

Call 408-793-5302 to schedule an appointment for a master plan submittal. Staff in Building, Planning, Fire Prevention, and Public Works will review your plans.

Master plan submittal package

  1. An accurate, complete submittal package is required and must include:
    Architectural information, plans, elevations, sections, and details
  2. Structural information, plans, elevations, sections, and details
  3. Structural calculations
  4. Title 24 energy documents, as applicable
  5. Truss plans and calculations, as applicable
  6. Indication of Fire sprinklers: Provide a statement as to whether the standard construction plan layout proposes to be equipped with an automatic fire sprinkler system.
  7. Geotechnical investigation report, as applicable
  8. For ADUs, you may use code minimum soil valuation for foundation design, or pre-scripted footing sizes if conventional construction is used, or match existing foundation.
  9. A standard site plan as reference is optional.

An incomplete package will not be accepted. If you must resubmit, another appointment will need to be scheduled.

IMPORTANT: You will need to refile your master plan when the City adopts new building codes, building policies, or zoning changes that apply to the plans. The City will notify you if such changes take place.

HOMEOWNERS: I'm using preapproved plans. How do I proceed?

Before undertaking any kind of ADU project, including a preapproved design, homeowners should review the ADU Universal Checklist to identify if their project or site is subject to any special permits, clearances, or variances, and to make sure their project concept complies with the City's zoning codes.

Preapproved construction plans must still be submitted as part of a site-specific ADU permit application. 

Plan Submittal Requirements

See Bulletin #211-ADU Building Plans Submittal Checklist for direction on format and content of the submittal package. A site-specific application with preapproved plans must include:

  1. Project site plan/plot plan that includes scope of work, parcel boundaries, dimensions, street name, and location of any utilities and easements
  2. Location and dimensions of the primary dwelling unit and ADU, including distances from the main dwelling to the ADU and to parcel boundaries
  3. Architectural information, plans, elevations, sections, and details
  4. Structural information, plans, elevations, sections, and details
  5. Structural calculations as reference (an updated calculation is needed for minor changes).
  6. Title 24 energy documents as reference (an updated document is needed for minor changes).
  7. Foundation information

Plan Review Process

For projects with no changes to the preapproved plans. For projects adhering to the approved master plan without any changes, call 408-793-5302 to make an appointment for our lowest-cost Over-The-Counter service.

For projects with minor changes to the preapproved plans. Call 408-793-5302 to make an appointment for plan review. The plan review supervisor may direct that the plans be submitted for regular Plan Review Service if changes exceed what the City considers as minor. Minor changes are limited to:

  • One load-bearing beam or wall (shear wall); and
  • No more than 25 percent of change to the Master Plan configuration.


Visit the Building Fees page, open the Building Fee Schedule and look at the Single-Family Residential fee section. For ADUs, use the addition/alteration table to determine the fee. Other fees such as Public Works clearance fees, parkland fees (not applicable to projects under 750 sf), and school fees, and all applicable taxes, must be paid prior to permit issuance. The building permit fee is due at the time of application.

Preapproved Vendors

The City of San José has preapproved plans offered by the following vendors--these are all for detached ADUs:

Company:  Abodu
What's Preapproved:  495 sq. ft. ADU foundation-only with State-approved factory-built housing
Contact: or 650-398-0158

Company:  Acton ADU
What's Preapproved:  
     • 364 sq. ft. 1 bedroom ADU
440 sq. ft. 1 bedroom ADU
560 sq. ft  1 bedroom ADU
Contact: or 408-369-1103

Company: prefabADU
What's Preapproved:  
     • 325 sq. ft.  ADU foundation-only with State-approved factory-built housing
     • 495 sq. ft.  ADU foundation-only with State-approved factory-built housing
Contact: or 650-398-0158
Contact: or 707-429-3300


Our ADU Ally can answer questions concerning preapproved plans:
Phone: 408-793-5302

This information is also found and can be downloaded as Bulletin #212 - ADU & Single-Family Master Plan Program.