ADU Ready Design Submissions

Permit Sonoma invites licensed architects and general contractors to submit detached accessory dwelling unit (ADU) plans to add to our Pre-reviewed ADU Design Gallery. This process meets requirements set forth by Government Code Section 65852.27 and supports the County’s responding ADU Ready program.

How Your Plans Will be Used if Approved as Pre-reviewed

• Plan Listing. Once your ADU plans have been approved as pre-reviewed, basic plan attributes and your contact information will be added to Permit Sonoma’s Pre-reviewed ADU Design Gallery for the remaining duration of the code cycle it was approved under. You will become referenced as a “plan vendor” and project applicants looking to build ADUs under the ADU-Ready program may contact you to obtain a pre-reviewed ADU plan package.
• Licensing and Fees. Project applicants are responsible for licensing fees and limitations on use as required by plan vendors.
• Plan Integration. Pre-reviewed ADU plans may not stand alone and must be integrated with a specific site and project scope. Project applicants and their teams are responsible for this integration and the procurement of a complete building permit application. Plan vendors may choose to offer services to assist in this process.

Benefits of Submitting Your Plans

• Income. Once plans are approved as pre-reviewed, licensing fees for the same pre-reviewed ADU package may be sold repeatedly until the end of the code cycle.
• Client Reach. Vendors’ plans and contact information will be listed in our online gallery to be perused by potential ADU project applicants. Applicants may reach out to purchase a pre-reviewed ADU plan package, but they may also be looking for help with a custom ADU project outside of the ADU Ready program.

Design Submittal Process

• Application type. Plan vendors will submit stock plan (STK) applications for the pre-review of accessory dwelling unit (ADU) designs.
• Submittal Requirements and Fees.
  • Include a a cover sheet specific to the ADU, plans, details, calculations, and supporting documents including California Energy Code Analysis, , BPC-066 CALGreen Mandatory Measures checklist, and CNI-033 Statement of Special Inspection in your STK application. Policy Document 9-4-5 Stock Plan Procedure is currently undergoing revisions and should be published soon to provide additional guidance.
    • Review BPC-002 Residential Plan Checklist for details on submission items.
  • Review BPC-002 Residential Plan Checklist for additional details on submission items.
  • Visit our online permitting website to start a new application under New Building Permit – Stock Plans (STK).
  • General Design & Development Standards
    • ADUs should be designed to meet all adopted codes such as those for building, energy, and fire safety. A partial list is referenced in BPC-002 Residential Plan Checklist.
    • ADUs must meet minimum building code standards for living space and must have permanent provisions for living, sleeping, eating, cooking, and sanitation.
    • Common size categories. An ADU plan submitted for pre-review may be of any size within maximum code limits, though certain sizes may be desirable for those looking to minimize fees or maximize the size of their ADU. Some relevant cutoffs are listed below:
      • Square Footage.
        • Inland:
          • ≤ 1200 square feet – All new ADUs
          • ≤ 800 square feet – ADUs may override certain setback requirements
          • ≤ 750 square feet – ADUs are exempt from park and traffic impact fees
          • ≤ 500 square feet – ADUs are exempt from school fees
        • Coastal Zone:
          • ≤ 1000 square feet – ADUs with a recorded affordable housing agreement
          • ≤ 840 square feet – All new ADUs (non-Affordable)
      • Height
        • Inland:
          • ≤ 18 - 35 feet, dependent on base zoning – ADUs on lots with existing or proposed single-family dwellings
          • ≤ 18 feet – ADUs on lots with existing or proposed multifamily dwellings
        • Coastal Zone:
          • ≤ 16 feet – All new ADUs in the coastal zone
      • Bedrooms
        • Many residences in the unincorporated county rely on well and septic systems. The quantity of additional bedrooms allowed on a property will depend on water availability and waste system capacity. To accommodate this a variety of 1-, 2-, and 3-bedroom designs would ideally be hosted in the pre-reviewed ADU plan gallery.

Renewing a Listing

Pre-reviewed plans are only maintained in our stock gallery until the end of the code cycle they were approved under. If you wish to renew your listing, submit a new STK application referencing the STK number assigned to the original listing and highlighting updates made for any new applicable code requirements.

Requesting Removal of Posted Plans

To request removal of your designs from our Pre-reviewed ADU Design Gallery, submit your request via email to PermitSonoma@sonoma-county.org.
Be sure to include the following information in your request:

• The STK number if one was assigned.
• Your name and company name.
• The name of the listed design.
• Proof of design ownership.