Unit Addition FAQ

Addition of Dwelling Units


PDF iconFAQ Addition of Dwelling Units per Ord 30-15.pdf

General Information
Screening Process
Permit Application
Property Tax
Planning Requirements
Additional Information



  1. What is the program for addition of dwelling units in San Francisco?

It is a program under Ordinance No. 30-15 that allows applicant to add dwelling units within existing building envelope based upon permits for Mandatory Seismic Retrofitting under SFBC Chapter 34B, or voluntary seismic retrofitting per AB-094, or located in Supervisorial Districts 8 and 3 specified by Ordinance Nos. 161-15 and 162-15.

  1. Where may I find additional information regarding unit addition?

Please visit DBI’s homepage: http://sfdbi.org/unitaddition, and download Information Sheet No. G-23:  http://sfdbi.org/sites/sfdbi.org/files/IS%20G-23.pdf or visit DBI at 1660 Mission Street – San Francisco CA 94103 to the Unit Addition Counter on the 1st Floor. A telephone hotline (415-558-6117) and an email hotline: Softstory@sfgov.org had been set up and in operation to answer questions on unit addition.

  1. Are single-family homes eligible to add dwelling units?

Accessory dwelling units associated with a building undergoing seismic retrofitting may not be constructed on properties zoned RH-1 or RH-1(D). Accessory dwelling units located in District 3 and 8 may not be constructed on properties zoned RH-1(D).

Single family zones cannot take advantage of the Program; however a single family home in a RH-2 or RH-3 District could enter into the Program.

  1. I understand that RH-1 or RH-1(D) zoning district is excluded from the program, how do I find out my zoning district?

You may visit San Francisco Property Information Map at https://sfplanninggis.org/pim/ or Planning Information Center (PIC) at 1660 Mission Street, 1st Floor, or call (415)558-6377.

  1. Is there a limit on the number of additional units?

In District 3, for buildings with 4 existing dwelling units or fewer, 1 accessory dwelling unit (ADU) is permitted; for building that have more than 4 existing dwelling units, there is no limit on the number of ADUs.

In District 8, for buildings with 10 existing dwelling units of fewer, 1 ADU is permitted; for buildings with more than 10 existing dwelling units, 2 ADUs are permitted.

For buildings undergoing seismic retrofitting, there is no limit to the number of ADUs. Units must meet Building Code requirements. In addition, units must meet Planning Code requirements including partial exposure.

  1. May I use space from an existing dwelling unit to construct a new unit?

No, accessory dwelling unit shall not be constructed using space from an existing dwelling unit.

  1. Are the additional units under rent control?

If the building is under rent control, the added unit will also be under rent control. If the building is not under rent control, the added unit will not be under rent control.

  1. How much will it cost to add dwelling units meet San Francisco Building Code requirements?

  Depending upon the scope of adding the dwelling units, the cost will vary. Please consult a licensed civil or structural engineer, architect or a licensed contractor, to obtain accurate estimates and multiple bids.

In general, change from 2 units to 3 units is much more expensive, since it may trigger sprinklers and other         requirements from Fire. Other cases are less expensive.

  1. Does DBI have a list of pre-qualified engineers/architects or licensed contractors who specialize in unit addition?

No. Please contact the Board for Professional Engineers at Tel. 866/780-5370; the Contractors State License Board at Tel. 800/321-2752; the Structural Engineers of Northern California (SEAONC), at Tel. 415/974-5147; and American Institute of Architects (AIA), at Tel. 415/362-7397. You also should visit their respective web sites for additional information.

  1. How does DBI and Fire determine code equivalencies?

Through pre-application meeting (see AB-028) or AB-005, DBI and Fire shall determine whether building code equivalencies are applicable to any code issues related to unit addition.

  1. Is there a notification process?

Not required, since the added unit is within building envelope.

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  1. Does DBI provide a screening service?

DBI will provide an initial screening process that is non-binding to help owners understand their eligibility for adding the dwelling units before filing an official application. Owners may hire an engineer or design professional or contractor for representation. The owner or professional agent may go to the Unit Addition Counter on the 1st Floor of 1660 Mission Street to meet informally with DBI staff to determine their eligibility, consult with the Planning Department if applicable. Following the screening process, the owner or professional agent may formally apply for unit addition with the Planning Department and submit building permit applications with DBI.

  1. What is the screening form?

The Screening Form establishes the applicant’s eligibility for the unit addition program. The screening form will not be used by the Department in an official capacity.

  1. Can applicant submit a permit application to add the dwelling unit under the Unit Addition Program without submitting the screening form? 

No. Applicant cannot submit a permit application to add the dwelling unit under the Unit Addition Program without filing the screening form at DBI’s Unit Addition Counter.

  1. How long is the review time for the screening form?

Screening Form is reviewed on the spot.

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PERMIT APPLICATION:                               

  1. How to identify the newly added unit on the permit application form for unit addition?

On the permit application form 3/8, clearly identify the different number of dwelling units under item (9A) “Legal description of existing building” and (9) “Description of building after proposed alteration”.

  1. Any other requirements on completing permit application form for unit addition?

The permit application form 3/8 including new or remodeling of kitchen or bathroom shall indicate that both electrical and plumbing permits are required.

  1. What is the timeframe for permit approval of unit addition work?

     This depends upon the overall scope of work. After Planning approval, small scopes of work may qualify to be reviewed and potentially approved over-the-counter and while you wait. Larger scopes of work may be reviewed within four weeks after Planning Department approval.

  1. If we are adding more than one unit, can it be under one permit?

Yes, added units may be under one permit. Separate permit is needed for soft story work. Both permits may refer to the same plans.

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  1. Will added dwelling units be reported to the Assessor?

Added dwelling units shall be reported to the Assessor when completed for applicable property tax assessment.

  1. Will the Tax Assessor reassess my building under this unit addition program?

      Yes. Please call the Assessor’s Office, Tel. 415/554-5596, for this information. Since the assessed value increases, your property taxes may be raised. 


  1. Which aspects of the Planning Code will be waived?

The Zoning Administrator may waive rear yard, parking, open space, and density requirements and may reduce the amount of dwelling unit exposure required. Typically a new dwelling unit must face a street or conforming rear yard; however, the Zoning Administrator may reduce this requirement so that qualifying windows may face an open area that is no less than 15’X15’ and is open to the sky. A qualifying window is defined in the Housing Code and must be located within a living area (e.g. living room, dining room, bedroom, or kitchen) that is at least 120 square feet in area.

  1. What Planning Code Requirements must be met to add an accessory unit?

All other Planning Code requirements including landscaping, permeable surfaces, and bicycle parking are required to be met. In addition, each unit must meet the reduced exposure requirement stated above.

  1. Is there design review associated with the addition of accessory units?

If the addition of accessory units requires exterior changes on a visible façade, design review and historic preservation review may be required.

  1. Can existing parking spaces and/or existing storage spaces be utilized to construct additional units?

Existing parking spaces can be utilized to construct additional units in certain situations. Covered multi-unit building after March 13, 1991, may need to retain accessible parking. Please consult the Planning Department Information Center (PIC) with specific questions. Existing storage spaces can be utilized to construct additional unit.

  1. I have one parking space. If I add one additional unit, will Planning require me to add more parking for unit addition?

No. Under this program, parking requirements may be waived by the Zoning Administrator.

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  1. Does each unit require bath, kitchen and sleeping?

Yes. Studio unit is okay.

  1. Is excavation down allowed?


  1. What will be triggered if there is change of use?

For most unit addition, there is no change of use, except when R3 occupancy is changed to R2 occupancy. In such case, fire sprinkler requirements will be triggered. (See Information Sheet FS-05) Please indicate the unit count change on the permit.

  1. I want to separate the water/electrical/gas meters for the unit. This may require adding a separate         address for the unit. Can I apply to add a new address for the unit?

Yes. Assigning new street addresses is by appointment only. After permit for addition dwelling unit is issued, please request the appointment via email with all relevant information to: Wai-Fong.Cheung@sfgov.org

  1. Which is easier/faster – to add unit or legalize unit?

Adding and legalizing unit are different in scope. It depends on what work you need to do associated with the legalization or addition of an accessory unit.

  1. I have a 4-unit building. I had completed work for voluntary soft story retrofit per AB-094. Now I want to apply for a permit to add one dwelling unit per Ordinance 30-15. Will that trigger Mandatory Soft Story Retrofit per SFBC Chapter 34B?

Yes. To handle this situation, go to the Soft Story Counter at DBI when you file for building permit. You would need to complete a screening form under Mandatory Soft Story Program for exemption based on completed work per AB-094.

  1. If I want to do full seismic retrofit, can I add a unit per Ordinance 30-15?

Yes. You would have to file two separate permits, one for the soft story retrofit, and another one for the remaining seismic work. 

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Revised 03-11-16