Planning Director Bulletin No. 8: Streamlined Housing Development

This Bulletin is an overview of two ministerial streamlining programs for small residential projects. Senate Bill 9 allows duplexes and lot splits for certain parcels in single-family RH-1 zoning districts. Senate Bill 684 allows up to 10 units on certain parcels.

First Issued: December 2021, updated September 2025
References: SB 9 (CA Govt. Code Sections 65852.21, 66452.6, and 66411.7) and SB 684 (CA Govt. Code Section 66499.41, 65852.28, and 65913.4.5)

Introduction

Senate Bill 9

Senate Bill 9 requires ministerial approval of a housing development of two units in a single-family zone in San Francisco, RH-1, RH-1D, RH-1S, the subdivision of an RH-1 parcel into two parcels, or both.

Overview

To be eligible for SB 9 ministerial approval, a housing development project must meet the following requirements.

Zoning: The parcel must be located in an RH-1, RH-1D, or RH-1S zoning district. To determine the parcel’s zoning, consult the SF Property Information Map.

Pre-application Occupancy: The parcel must be owner-occupied or vacant for three years prior to the application. A project is ineligible if the proposal includes the demolition or alteration of a housing unit occupied by tenants in the three years prior to an application. Applicants will be required to provide proof of occupancy for three years prior to application, as described in the SB-9 project application forms.

Rental Pricing Controls: Parcels are ineligible if they include existing units subject to local rent control regulations. The following are typically not subject to rental pricing controls: single-family homes, condominiums, ADUs permitted under the State program, and units built after 1979. Applicants will be required to provide unit count and building construction date of any existing buildings to determine eligibility.

Ellis Act evictions: Parcels are ineligible if they include a unit where the Ellis Act has been used in the fifteen years prior to an SB 9 project application. To determine if a unit on the parcel has been subject to an Ellis Act eviction, consult with the San Francisco Rent Board.

Historic Resources: Parcels are ineligible for SB 9 if located within a historic or landmark district under State law or if designated or listed as a landmark or historic property or district under local law Planning Code Article 10 or 11. To determine if the parcel is designated or listed as a landmark or historic property or located in a district under local law, consult the SF Property Information Map.

Eligibility Criteria for All SB 9 Projects

Prohibition of Short-Term Rentals: SB 9 requires that the rental of any unit created under an SB 9 project be for a term longer than 30 days.

Original Parcel Size: Only parcels 2,400 square feet and larger are eligible for a ministerial lot split.

Resulting Parcel Size: An SB 9 lot split cannot result in a parcel more than 60% or less than 40% of the size of the original lot, and both newly created parcels must be at least 1,200 square feet.

Prior Lot Splits: Any parcel established through the prior exercise of an urban lot split under SB 9 is not eligible. You may not use SB 9 to subdivide a parcel twice.

Adjacent Lot Splits: Parcels where either the owner of the parcel, or any person acting in concert with the owner, has previously subdivided an adjacent parcel using an urban lot split under SB 9 are also not eligible.

Post-Project Owner Occupancy: SB 9 lot split projects require the applicant sign 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 approved lot split. This requirement does not apply if the applicant is a community land trust or a qualified nonprofit corporation.

Lot Split Easements: Projects that include a lot split may require easements for utility connections and physical access, depending on the lot split configuration. Easements must meet all applicable fire and building safety code requirements.

SB 9 Projects in San Francsico

SB 9 contains development standards and requirements that allow for a ministerial approval process and application of certain Planning Code regulations.

Objective Standards: SB 9 projects must comply with all objective requirements including zoning, subdivision, and design review standards that do not conflict with SB 9. The City cannot impose objective standards that would physically prevent the construction of up to two units or that would physically prevent either of the two units from being at least 800 square feet in floor area, except that the project must include four-foot setbacks from the side and rear lot lines outside of the buildable envelope.

In most cases, the allowable building envelope in a new structure should be able to accommodate two units of 800 square feet and meet objective Planning Code requirements including rear yard, height, open space, front setbacks, side setbacks, and exposure. The San Francisco Planning Commission adopted the San Francisco Design Standards on November 14, 2024.

Accessory Dwelling Units (ADUs): ADUs allowed by State Law may be included in SB 9 projects, depending on the project scope and design and the proposed ADU type. More information on ADU programs is available at Accessory Dwelling Units.

Non-Conforming Conditions: SB 9 prohibits the correction of nonconforming zoning conditions as a condition for ministerial approval of a lot split.

SB 9 Development Scenarios

Scenario 1 – SB 9 Parcel Development Scenarios for Projects That Do Not Use the Lot Split Provision: Without the lot split provisions, an SB 9 project could either demolish an existing single-family house and construct a new duplex, or convert the existing single-family structure into a duplex. This type of project does not require owner occupancy after project application unlike those also pursuing a lot split. Neither unit would be subject to rent control, and the units could be sold as condominiums at project completion. Parcels of any size are eligible for SB 9 development without a lot split, and although there are no minimum or maximum unit sizes required by SB 9, the City must allow each unit to be at least 800 square feet. The Accessory Dwelling Units that may be added in this scenario are State Program Accessory Dwelling Units.

Table 1 - No Lot Split

Scenario 2 – SB 9 Parcel Development Scenarios for Projects That Also Use the Lot Split Provision: The second path for SB 9 development is to split a single-family lot into two lots. Both lots must be at least 1,200 square feet. Neither lot can be more than 60% of the size of the original lot. This type of project requires an affidavit from the applicant that they intend to occupy one of the housing units as their principal residence for a minimum of three years from the date of the approved lot split, unless the applicant is a community land trust or a qualified nonprofit corporation. None of the primary units created on a parcel that was split under SB 9 would be subject to rent control, and the units could be sold independently at project completion. The Accessory Dwelling Units that may be added in this scenario are State Program Accessory Dwelling Units.

Table 2 - Lot Split

Please refer to the Streamlined Housing Development Senate Bill 9 Application for submittal requirements.

Senate Bill 684

Senate Bill 684 requires ministerial approval of eligible subdivisions and the development of 10 or fewer residential units.

Overview

To be eligible for streamlining, the project must meet all the following criteria.

Zoning: The subject parcel and development must be located on a parcel zoned multifamily residential uses, or a parcel that is vacant and zoned for single-family residential development. Vacant means having no permanent structure, unless the permanent structure is abandoned and uninhabitable as determined by the Department of Building Inspection. The following types of housing shall not be considered vacant:

• Housing that is subject to any form of rent or price control.
• Housing subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, very low, or extremely low incomes.
• Housing occupied by tenants within five years preceding the application, including housing that has been demolished or that the tenants have vacated prior to application submittal.

Location: The development must be located on a property that is not classified as prime farmland, wetlands, a high fire hazard severity zone, hazardous waste site, a delineated earthquake fault zone, a flood plain, a floodway, a community conservation plan area, a habitat for protected species, or under a conservation easement.

Hazardous Waste Site: The development must not be located on a property that is classified as a hazardous waste site as defined under CA Govt. Code Section 65852.28(a)(9)(D), unless the project sponsor has secured a uniform closure letter for an underground storage tank or a letter from the State Department of Public Health, State Water Resources Control Board, or the Department of Toxic Substance Control stating that the site is suitable for residential uses.

Existing Lot: The existing lot, or the lot proposed to be subdivided, must meet all of the following criteria:

• A lot zoned for multifamily uses must be no larger than five acres, and a vacant lot zoned for single-family residential development must be no larger than one and one-half acres.
• It must be surrounded on 75% of the perimeter by urban uses, defined as residential uses, commercial uses, retail, public institutional uses, transit, or transport passenger facilities.
• It was not established through the lot split provisions SB 684 CA Govt. Code Section 66499.41 or SB 9 CA Govt. Code Section 66411.7.

Demolition or Alteration of Residential Units: The project does not require the demolition or alteration of any of the following types of housing:

• Units subject to any form of rent or price control, or units subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, very low, or extremely low incomes.
• Units occupied by tenants within five years preceding the application, including housing that has been demolished or that the tenants have vacated prior to application submittal.
• Units that were subject to an Ellis Act eviction within 15 years preceding the application.

Project Size: The proposed subdivision will result in 10 or fewer parcels, and the housing development project on the lot proposed to be subdivided will contain 10 or fewer units.

Proposed Lot Requirements: The newly created parcels must meet all of the following criteria:

• Parcels in multifamily zoning districts must be at least 600 square feet in lot area, and vacant lots zoned for single-family residential development must be at least 1,200 square feet.
• They must be served by public water and municipal sewer system.
• They must meet all of the objective standards of the Subdivision Map Act.

Ownership: The housing units on the lot proposed to be subdivided are one of the following:

• Constructed on fee-simple ownership lots.
• Part of a common interest development.
• Part of a housing cooperative as defined in Section 817 of the Civil Code.
• Constructed on land owned by a Community Land Trust that meets all the requirements of CA Govt. Code Section 66499.41(a)(4)(D).
• Part of a tenancy in common, as described in Section 685 of the Civil Code.

Density: The project must create at least one new residential unit on each of the resulting parcels, except for resulting parcels with existing legally permitted residential structures or that are reserved for internal circulation, open space or common area. The project must construct a minimum number of units, as follows:

• If the project is on a lot that is identified in the City’s Housing Element, at least as many units as projected for that parcel in the Housing Element Site Inventory. If the parcel includes any portion of the share of the regional housing need for low- or very low-income households, it must include as many affordable units as projected in the housing element deed restriction for 45 years.
• If the project is on a lot that is not identified in the City’s Housing Element, the project must result in at least as many units as 66% of the maximum allowable residential density.
• Note that the City may not preclude an applicant from constructing at a density of 30 units per acre, or one unit for every 1,452 square feet of lot area. Please see below for additional information on how to calculate the allowable density for an SB 684 project.

Average Unit Size: The average total area of floorspace for the proposed housing units does not exceed 1,750 net habitable square feet. Net habitable square feet means the finished and heated floor area fully enclosed by the inside surface of walls, windows, doors and partitions, and having a headroom of at least six and one-half feet, including working, living, eating, cooking, sleeping, stair, hall, service, and storage areas, but excluding garages, carports, parking spaces, cellars, half stories, and unfinished attics and basements.

Inclusionary Housing: Projects that propose 10 units must comply with the Inclusionary Housing Ordinance, Planning Code Section 415 et. seq.

Inclusionary Housing Standards: SB 684 projects must comply with all objective requirements including zoning, subdivision, and design review standards that do not conflict with the standards set forth in CA Govt. Code Section 66499.41 or CA Govt. Code Section 65852.28. The City cannot impose objective standards that would physically prevent the construction of an SB 684 project that complies with the requirements for density and average unit size set forth in state law, except that the project must include four-foot setbacks from the side and rear lot lines outside of the buildable envelope. Objective Planning Code requirements include rear yard, height, open space, front setbacks, side setbacks, and exposure. The San Francisco Planning Commission adopted the San Francisco Design Standards on November 14, 2024.

Existing Dwelling Units: The proposed subdivision will not result in any existing dwelling unit being alienable separate from the title to any other existing dwelling unit on the lot.

Additional Information

Accessory Dwelling Units (ADUs): ADUs allowed by State Law may be included in SB 684 projects, depending on the project scope and design and the proposed ADU type. Accessory dwelling units do not count towards the 10-unit maximum project size. Learn more about our ADU programs at Accessory Dwelling Units.

Maximum Density

An SB 684 project must comply with the underlying permitted density as set forth in the Planning Code, except that the City cannot preclude the applicant from developing less than 30 units per acre, or one unit per 1,452 square feet of lot area.

For example, if the project is in the RH-3 zoning district which permits three units by right, then an owner may subdivide an existing parcel, and build three units on each new parcel excluding ADUs, up to 10 units total. SB 684 does not provide the right to construct 10 units on a multifamily parcel which would not allow the development of 10 units under density.

Minimum Density

An SB 684 project must meet minimum density standards as set forth in CA Govt. Code Section 66499.41(a)(5). If the existing parcel is not identified in the Housing Element, then the project must construct at least 66% of the maximum allowable residential density that is permitted on the existing parcel.

For example, if the parcel is in the RH-3 zoning district that permits a maximum of three units, then the project must construct at least 66% of the maximum density, or two units. If the existing parcel is identified in the Housing Element, then the project must result in as many units as identified in the Housing Element, including existing units, up to a maximum of 10 units.

For example, a development lot is identified in the housing element to accommodate four units. There is an existing duplex on the lot. If the owner chooses to subdivide and construct under SB 684, the new project must include at least two units to achieve the density identified in the housing element, or four units total.

The San Francisco Housing Element Update 2022 includes three density scenarios Map 1, Map 2, and Map 3. To comply with the minimum density requirements in SB 684, the project must select the map with the highest possible density without exceeding 10 total project units. If all three maps establish a maximum density of more than 10 units, then the project may construct a maximum of 10 units.

How to determine the minimum density of an SB 684 Project:

1. Open the Housing Element Sites Inventory, Appendix B.4 on the Housing Element 2022 webpage. Note that the link will download an Excel spreadsheet.
2. Navigate to the tab at the bottom of the spreadsheet titled Table B -- Submitted -- Dec-22.
3. Locate the project address or APN. Hint: use the Find and Replace function, usually Ctrl+F.
   • If the parcel is not included on Table B, then it is not identified in the Housing Element, and the project must construct at least 66% of the maximum allowable residential density to qualify for SB 684. The maximum allowable residential density is the maximum number of units allowed by the zoning district on the subject parcel. More information on a property’s zoning can be found on the SF Property Information Map.
   • If the parcel is located on Table B, continue to the next step.
4. After locating the parcel, scroll to columns AE, AF and AG for that row to determine the maximum density allowed.
   • The Department will round up the number of units from any remainder 0.5 and above.
5. SB 684 requires a project to provide as many low-income or very-low income units as projected in the housing element. To determine the affordable housing requirement:
   • Determine which Map applies to the project: Map 1, Map 2 or Map 3.
   • Find the corresponding very-low income and low-income columns for that Map.
   • Map 1: Columns E and F.
   • Map 2: Columns I and J.
   • Map 3: Columns M and N.
   • Multiply the applicable columns by the site acreage, Column R.
   • Any fractional numbers will be rounded up from 0.5 and above.

For questions, you can call the Planning counter at 628.652.7300 or email pic@sfgov.org where planners are able to assist you.