Senate Bill 9

SB 9 allows properties within a “single-family residential zone” to be developed with two units and be subdivided into two parcels, irrespective of local development standards. SB 9 allows for the following two new types of development that must be reviewed ministerially, without discretionary action or public comment:

  • Two Unit Development: Allows a single-family residential parcel to be developed with two primary dwelling units instead of just one, including an Accessory Dwelling Unit (ADU) and a Junior Accessory Dwelling Unit (JADU), for a total of four dwelling units. 
  • Urban Lot Split: Allows a single-family residential parcel to be subdivided into two parcels and for each parcel to be developed with two primary dwelling units, or a primary dwelling unit and an ADU or JADU. The total number of allowable units resulting from an urban lot split is four units, with two on each parcel.

Applicability

Two-Unit Residential Developments or Urban Lot Splits are to be permitted within all Single-Family Residential Zoning Districts, with the following exceptions:

  1. Any parcel which would require demolition or alteration of any of the following housing types:
    1. Housing that is subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, or very low income
    2. Housing that is subject to any form of rent or price control
    3. Housing that has been occupied by a tenant within the last 3 years
    4. Housing with an Ellis Act eviction within the last 15 years
  2. Any parcel located within a Historic District or included on the Historic Resources Inventory
  3. Any parcel within a high or very high fire hazard severity zone, unless the development complies with applicable fire hazard mitigation measures
  4. Any parcel located within an earthquake fault zone, unless the development complies with applicable seismic protection building code standards 
  5. A proposed Two-Unit Residential Development that allows the demolition of more than 25 percent of the existing exterior structural walls, unless the Two-Unit Residential Development is on a site that has not been occupied by a tenant in the last three years
  6. Any parcel that is adjacent to another lot split by SB 9 by the same owner or “any person acting in concert with the owner”
  7. Any parcel that was created by a previous SB 9 Urban Lot Split

Permitting Process

Two Unit Development: The construction of up to two primary dwelling units, ADU, and JADU are approved ministerially and without a public hearing, subject to approval of a building permit. However, proposed dwelling units that comply with the setback requirements of the underlying zoning district may apply for Design Review approval prior to building permit submittal for the following:

  • A new multi-story main structure or multi-story accessory dwelling unit
  • The conversion of a single-story structure to a multi-story structure
  • A new structure over 18 feet in height or an existing structure that would exceed 18 feet in height as a result of the proposed construction

Urban Lot Splits are approved ministerially and without a public hearing, subject to approval of a Tentative Map and Parcel Map.

Development Standards Summary

ItemRequirement
Unit Size and Floor Area/Site Coverage
  • On a parcel that has not been subdivided as a result of an SB 9 Urban Lot Split, the maximum allowable floor area is determined by the net site area of the parcel, provided at least two 800 square foot dwelling units are permitted
  • On the two new parcels created by an Urban Lot Split, the maximum allowable floor area for each lot is proportional to the percentage of the lot split of the original lot (i.e. 40%/60%), provided at least two 800 square foot dwelling units are permitted on each lot
  • A dwelling unit constructed as a part of Two-Unit Development or Urban Lot Split located partially or entirely within the side or rear setback area of the underlying zoning district shall have a maximum floor area of one thousand square feet. 
Setbacks
  • Setbacks of the underlying zoning district are required from both the front and exterior side property lines
  • A minimum setback of four feet is required from the interior side and rear property lines
  • No setback shall be required for an existing structure or a structure constructed in the same location and to the same dimensions as an existing structure
  • Attached covered patios, accessory structures, HVAC mechanical equipment, and generators shall comply with the applicable setback requirements of the underlying zoning district
Building Height
  • Dwelling units are limited to one story and a height of 18 feet
  • Dwelling units shall not exceed a height of 16 feet when located within the side or rear setback area of the underlying zoning district
Parking
  • One covered parking space per unit is required, except no on-site parking is required for properties within one-half mile walking distance of either a high-quality transit corridor1 or a major bus stop2, or within one-block of a car share vehicle3
Decks
  • Rooftop decks are not permitted
Urban Lot Split Minimum Lot Size
  • Resulting lots must be roughly equal in size (no more than 60% or less than 40% of the original lot size)
  • Resulting lots shall be at least 1,200-square-feet
  • Resulting lots shall be at least 50% of the width of the original parcel
Urban Lot Split Owner Occupancy
  • An applicant for an Urban Lot Split will be required to sign and record an affidavit stating that the applicant intends to occupy one of the housing units as their principal residence for a minimum of three years from the date of the approval of the urban lot split or building occupancy approval
Street Frontage
  • Each parcel created by an Urban Lot Split shall adjoin the public right of way by means of a minimum twenty-foot street frontage or access easement.
Driveways
  • A parcel with an existing street frontage of less than 80 feet may have only one driveway curb cut, providing access to both lots created by an Urban Lot Split via a 20 foot wide access easement.
Rental
  • No dwelling unit shall be rented for a period of less than 30 days
Septic System
  • For any Two-Unit Residential Development that will be connected to an onsite septic system, a percolation test showing compliance with applicable public health and safety standards and completed within the last five years, or, if the percolation test has been recertified, within the last ten years

1 A transit corridor with fixed route bus service with service intervals no longer than 15 minutes during peak commute hours. 

2 A ‘ transit stop’ at the intersection of two or more major bus routes with a frequency of service interval of 15 minutes or less during the morning and afternoon peak commute periods. 

3 A motor vehicle that is operated as part of a regional fleet by a public or private car sharing company or organization and provides hourly or daily service.