The Complete San Jose ADU Requirements in 2021


ADU Answers + Resources compiled just for you.

  • Is a detached ADU allowed at this location? 
    • Contact the City Planning department to review by calling: 408-793-5302
  • What is the maximum floor area of a detached ADU? 
    • 1,000 sf maximum for a 9,000sf lot size. 1,200 sf maximum for a 9,000+sf lot size. 
  • What is the maximum height of a detached ADU?
    •  One story: 18 feet maximum. Two-story: 24 feet maximum
    • If the property includes a JADU, height of a detached ADU is 16 feet maximum per state law. 
  • How far must the ADU be set back from the front lot line?
    • Must be set back 45 feet minimum from front property line.
    • Rear/side setbacks less than 3 feet may be subject to fire mitigation measures, see p. 4.
    • A second story OR new ADU with greater than 40% rear yard coverage must be set back 4 feet from both rear and side property lines.
    • Corner lots: A 10-foot setback is required on the street side.
    • Lots ½ acre or greater along riparian corridors Minimum 100-foot setback required.
  • What is the sleeping area?
    • Up to two bedrooms are allowed, and the maximum bedroom size is 400 sf.
  • Does the property have a dedicated easement? 
    • Easements are described in the title report that came with the purchase of your home. Contact a title company if you need to obtain a report. Tract and parcel maps may show easements, but may be less accurate than a title report. Find these maps at the County Surveyor Record Index tool at
    • If you do have an easement – you must comply with the requirements of the easements, which may include no construction allowed in the easement area.
  • Is the property in a designated “geohazard” or “landslide” zone? 
  • Is the property in Flood Zones A, AE, AH, or AO?
  • Kitchen, Bathroom, Storage. Does your proposed ADU comply with these rules?
    • Kitchen – ADUs must have a sink, food preparation counter, storage, cabinets, and permanent cooking facilities such as a range or cooktop and oven.
    • Bathroom/s – For ADUs, up to two bathrooms are allowed, requiring a sink, toilet, and shower and/or bath facilities.
    • Storage – A closet or other enclosed storage area cannot exceed 60 sq. ft.
  • Second Story Window Sill Height. 
    • Sill height for any openings must be a minimum 5 feet from the floor for walls nearest to rear and side property lines.
  • Must off-street parking be provided for the ADU?
    • Exemptions: Many ADUs qualify for a parking exemption in accordance with state law. Please see the Parking Requirements page at for a list of the exemption criteria.
    • Parking space location: If you are required to provide a parking space, it must be located on a surface free of mud or dust. It may be located within the front and side setbacks of the property, with a minimum driveway length of 18 feet. 
  • Is a minimum flow of 1,000 gpm at 20 psi available at the closest hydrant? 
    • Ask your Water Company for this information. Send an email with “ADU WATER FLOW REQUEST” in the subject line and present this information:
      • Your name
      • Street name and address of the project
      • Nearest cross street to that location
    • Submit the letter from the Water Company that contains this water flow data with your building permit application.
    • DON’T WAIT! A top reason for permit issuance delays is not having this letter. Your water company will respond, so contact them today. Find Water Company contact information at the ADU Fire Requirements webpage:
    • If the flow is other than 1,000 gpm at 20 psi, Fire staff will review flow data and will evaluate if additional fire safety measures are required.
  • Are all exterior walls of the ADU within 600 feet of a fire hydrant?
    • On the Site Plan Vicinity Map for plan submittal, mark one or more locations of fire hydrants closest to the project. Indicate the distance from the hydrant/s to the farthest exterior wall of the ADU, using the minimum 3-foot clear path of travel.
    • If there is not a hydrant proximate to your ADU, your project may require a Fire Variance that entails additional safety measures. Call 408-535-7750 for direction. Find the Variance application
  • Does your primary residence have a fire sprinkler system?
    • Then your ADU must have a fire sprinkler system.
  • Does the ADU have its own address and is the address visible and legible from the street?
  • Will constructing an ADU require removal of an ordinance-size or heritage tree?
  • What fees will I be required to pay?
(example costs of an ADU)

Written: 7/30/21
Have any other questions? Contacts us:


San Jose ADU FAQs

ADU Universal Checklist

Office of the Assessor, Santa Clara County

ADU Handbook HCD

San Jose Plan + Permit Process

Smart Asset (property taxes in San Jose)

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