Urban Lot Split (SB-9)

An urban lot split is the subdivision of an existing legal parcel into two new parcels in eligible areas as allowed by the County Code.

To apply for urban lot split, complete the process outlined below.

Updated Regulations
On June 3, 2025, the Board of Supervisors adopted updated regulations relating to urban lot splits (County Code Section 21.02.041), which take effect July 3, 2025.
Updated regulations include:
 
  • Urban Lot Split Pre-Screening Checklist. An urban lot split application is required to include a checklist certifying the proposed project complies with regulations that may impact the lot split design and the number of allowed dwelling units.
  • Site layout plan. An urban lot split application is required to include a site layout plan for the proposed buildout of the resulting parcels, including existing or anticipated single-family dwellings, urban dwellings, and/or accessory dwellings.
  • Number of dwelling units. Parcels resulting from urban lot splits are allowed a maximum of 2 dwelling units, including single-family dwellings, urban dwellings, and accessory dwellings.
  • Eligible areas. Eligible areas include urban areas and urban clusters as designated by either the 2010 or 2020 census data or areas within a County Urban Reserve Line, not including exclusion areas defined in State Law.
  • Owner occupancy. The property owner shall sign an affidavit stating they intend to occupy one of the primary dwellings on one of the resulting parcels as their principal residence (1) for a minimum of three years from the final parcel map recordation date for the urban lot split or (2) for a minimum of three years from the date the first dwelling unit permit is finaled if there are no existing residences at the time of final parcel map recordation, unless the owner is a community land trust or qualified non-profit corporation.

Last updated: June 20, 2025

 

What is the process?

Step 1: Minimum Eligibility

Before applying, a parcel needs to meet minimum eligibility standards and requirements.  To check if your property is eligible for an Urban Lot Split, please follow the steps below:

  1. Use this link to view SB-9 Eligibility information in our interactive map LandUseView
  2. Search your Assessor's Parcel Number (APN) OR address in the search bar in the top right corner or zoom to your property location.
  3. Click on your parcel to select it and confirm the 'Urban Lot Split Eligible' criteria is marked 'Yes'.

Step 2: Urban Lot Split Pre-Screening Checklist

Parcels meeting mimium eligibility requirements may need to comply with additional health and safety standards.  To see which health and safety standards will apply to your project please complete the Urban Lot Split Pre-Screening Checklist.  Please note that compliance with relevant health and safety standards may impact the lot split design and number of allowed dwelling units.

Step 3: Complete a Cost Accounting Agreement

A completed Cost Accounting Agreement is required. Please download and complete a Cost Accounting Agreement.

Step 4: Complete an Application Package

A completed Application Package is required. Please download and complete an Urban Lot Split Application Package.

Step 5: Obtain a Map Number

A Map Number is required. Please Request a Map Number.

Once you have the autogenerated map number, ensure the map number is printed on the tentative map. 

Step 6: Apply Online

Please apply for an urban lot split through the online service PermitSLO.

*** Please ensure all documents reflect the map number. ***

  1. Select Subdivision Application type and click Apply
  2. Login by providing your email address and clicking "Next", or "Create an account", if you are a new user.
  3. Follow the step-by-step instructions.
  4. Upload the following before clicking Submit:
    1. Urban Lot Split Pre-Screening Checklist
    2. Planning Cost Accounting Agreement
    3. Urban Lot Split Application Package
    4. Public Works Cost Accounting Agreement (C&I Agreements)
    5. Tentative Map and Site Layout Plan (showing proposed buildout)
    6. Additional Required Information


 

*Digital Copies are now required with submission*

Planning staff will look over the application submittal package and contact the primary contact with any questions.

Step 7: Pay Invoice

Planning staff will email the billing contact an invoice. Pay invoice here*.

Once the invoice is paid, the project review timeline will begin.

Please note for all Planning and Building applications, after 15 days of non-payment of invoice, the application will be voided and resubmittal will be required.

Step 8: Director Review

Department of Planning & Building staff will review the Eligibilty Checklist, Cost Accounting Agreement, Application Package, Tentative Map, and other supporting documentation.

Step 9: Record Subdivision

The applicant must record the approved subdivision within two years of its approval date.

Step 10: Extend Approval (Optional)

The applicant may request a time extension, in writing, to extend the approval date for one year. The maximum number of available time extensions is based on the subdivision entitlement type.

When and where is this service offered?

This service is available throughout the year during regular business hours except during scheduled holidays.