ADU Jurisdiction Guide: City of South San Francisco
Fees and Regulations (July 2022)

ADU-allowed Zones

Having ADU on your property is allowed as long as your lot is zoned for residential use (exceptions may vary) and as long as you have an existing single-family home or a multi-family building. 

Single-unit dwelling:

  • One (1) ADU – within the existing space of the property
  • One (1) JADU per lot

Multiple-unit dwelling:

  • 25% of existing units or one (1) unit, whichever is greater
  • Two (2) detached ADUs

ADU Size Limitations

A local government may, by ordinance, establish minimum and maximum unit size requirements for both attached and detached ADUs. 

However, maximum unit size requirements with one bedroom must be at least 850 square feet and 1,000 square feet for ADUs with more than one bedroom. 

For local agencies without an ordinance, maximum unit sizes are 1,200 square feet for a new detached ADU and up to 50 percent of the floor area of the existing primary dwelling for an attached ADU (at least 800 square feet).

ADU Building Height

16 feet

Minimum Lot Size

No minimum

Setbacks Requirements

  • Front: Setback requirement of the Zoning District (RL-8)
  • Interior/Street Side: 4 feet
  • Rear: 4 feet
  • Distance between structures: 6 feet
  • The existing living area or accessory structure converted to ADU: No setback requirement

Parking Space Requirements

  • Parking requirements for Detached ADUs shall not exceed one parking space per unit or bedroom, whichever is less. These spaces may be provided as tandem parking on a driveway. Guest parking spaces shall not be required for ADUs under any circumstances.
  • However, no additional parking is required when at least one of these scenarios apply:
    • The ADU is located within a half mile of a public transit stop.
    • The ADU is within a designated historic district.
    • The ADU is within a block from car sharing facilities.
    • The ADU is located where on-street parking permits are required but not offered for ADUs.
  • Conversion ADUs and JADUs don’t require any parking.

Owner Occupancy Requirements


Other Regulations

  • Only an ADU constructed with a new single-unit or multiple-unit residential dwelling shall be required to have a new or separate utility connection.
  • If required the cost will be proportional to the size in square feet of the ADU or its DFU (Drainage Fixture Unit) values. (SSF MC § 20.350.035(L)(2))
  • Same Principle above applies to ADU sewer line requirements.
  • State ADU law does not allow for the limitation on the number of bedrooms of an ADU. 
  • Local agencies may require that the property be used for rentals of terms longer than 30 days. ADUs permitted ministerially, under subdivision (e), shall be rented for terms longer than 30 days
  • New or separate utility connections may be required, but connection fees or capacity charges shall be proportional to the impact of the ADU on the sewer or water systems.
  • Fire Sprinklers are not required for a new ADU if they are not required in the primary residence. 
  • Newly constructed ADUs are subject to the Energy Code requirement to provide solar panels if the unit(s) is a non-manufactured, detached ADU.
  • ADU Entry Access is required. 

ADU Permit Fees

Building Permit Fees: Approximately 10% of the valuation, including Plan Check and MEPs, Plot plans, floor plans, and structural pages.

Sample Fees:

  • ADU 1(429 sq ft. attached): $5,928
  • ADU 2 (640 sq ft. above garage): $6,997


Impact Fees

(3) (A) A local agency, special district, or water corporation shall not impose any impact fee upon the development of an accessory dwelling unit less than 750 square feet. Any impact fees charged for an accessory dwelling unit of 750 square feet or more shall be charged proportionately in relation to the square footage of the primary dwelling unit.

Source: AB-68 Land Use: Accessory Dwelling Units


We hope this quick reference guide helps you out in your ADU project. Part of our service if you build with us is the full service of our in-house permit technician who handle the processing of your permit on your behalf with no mark-ups. 

If you’re interested in building with ADU.Works, please don’t hesitate to book a consultation with us or give us a quick call through our number +1 (650) 227 4810. We’ll gladly discuss the specifications of your permit processing and accommodate any questions you may have. Our team looks forward to hearing from you.

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