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Streamlined Housing Developments


If a property owner would like to split their lot or build additional residential units, Senate Bill 9 (2021) can help streamline the process for qualifying properties. SB 9 can be used in three ways:

  1. A Housing Development: Add up to two residential units to an existing lot.
  2. An Urban Lot Split: Split an existing lot into two new lots.
  3. A Housing Development and an Urban Lot Split: Split an existing lot in two new lots and add up to two new residential units on each of the resulting lots.

The following identifies the background, process, and required information and materials for a ministerial application to split a lot and/or build new residential units on a qualifying property using Government Code Sections 65852.21 and 66411.7 (commonly known as “SB 9”).


Senate Bill 9 was signed into law by Governor Newsom on September 16, 2021 to address the ongoing statewide housing crisis. Effective January 1, 2022, Government Code Sections 65852.21 and 66411.7 allow a property owner to split a lot into two and build up to two new residential units through a ministerial permitting process if the property is within a single-family residential zone and a U.S. Census urban area, and meets certain requirements. The ministerial process allows for project permitting without hearing or environmental review under the California Environmental Quality Act (CEQA).

Process and Required Application Materials

Step 1: Review Requirements and Complete an Eligibility Checklist

The first step is to review the requirements to see if a property may be eligible. Completing the Preliminary Site Eligibility Checklist will help determine whether your property meets the criteria. Gather documentation that demonstrates eligibility using the resources provided on the checklist.

Permit Sonoma has developed a GIS map to help property owners evaluate whether a parcel may be eligible for an SB 9 project. This map should be used in conjunction with the SB 9 Preliminary Site Eligibility Checklist. Please note that the map is a screening tool, and does not formally determine eligibility or reflect site-specific conditions.


Step 2: Check with a Planner

Once you have reviewed the requirements and researched whether the property may be eligible, meet with a planner at Permit Sonoma during office hours to discuss the site’s qualifications and receive a preliminary eligibility determination. Scheduled appointments are not required nor offered at this time. When visiting Permit Sonoma, bring any eligibility documentation you have gathered. Documentation for all eligibility criteria is highly recommended. A planner will review the checklist and documentation, then provide a preliminary eligibility determination. A planner’s determination is not binding; it is the applicant’s responsibility to satisfactorily demonstrate that the project meets eligibility criteria at the time that a formal Planning application is submitted.

Step 3: Submit a Complete Application

Once steps 1 and 2 are completed, the project applicant must submit a complete Planning application and pay the required application fees. A complete application must include all of the required application materials. If the project only includes a lot spit, the project will be processed as a Minor Subdivision. If the project only includes a two-unit housing proposal, the project will be processed as a Zoning Permit. If the project involves both a lot split and housing proposal, the project will be processed as a Planning Project.

Submit an application electronically:

Submit electronic applications


Step 4: Timelines for Ministerial Review

After application fees are paid, the project will be assigned to a planner who will review the application for completeness. Within 30 days of application payment, the project planner will notify the applicant whether the application is complete, incomplete, or determined to be ineligible for SB 9 processing. Action on the application will be taken within 60 days of the project planner’s confirmation that the project qualifies for ministerial approval(s) under SB 9. An approved SB 9 project will be subject to standard conditions of approval.

Step 5: Submit Construction Permits and/or Submit the Parcel Map

After the Planning application is approved, the project applicant may submit construction permits for concurrent plan check, which may include grading, building, encroachment, or other permit types, and submit a Parcel Map to the County Surveyor for review. Prior to Permit Sonoma’s clearance to record the Parcel Map, and/or issuance of construction permits, the applicant must demonstrate that the project complies with standard conditions of approval.


More Questions?

Visit us at the office to speak with a Planner, or staff from other divisions including Fire Prevention, Well and Septic, Building Plan Check, or Engineering.

You can connect with a Planner by emailing Find contact information for other divisions on the Permit Sonoma About Us page.

Additional Resources