Junior Accessory Dwelling Units

Junior Accessory Dwelling Units (JADUs) are a very small living unit (up to 500 square feet) created out of a bedroom within an existing single family home.

Accessory Dwelling Units vs. Junior Accessory Dwelling Units
Find out which situation applies to your property.

Changes in State law related to junior accessory dwelling units took effect January 1, 2020

Current regulations based on State law (Gov. Code Section 65852.22) are summarized below. As of January 1, 2020, the County's JADU ordinance (Sec. 26-88-061 of the Zoning Ordinance) no longer applies. 



  • Located in an existing single-family dwelling.
  • Created within an existing, legal bedroom.
  • Maximum size of 500 square feet.
  • Has an efficiency kitchen. (See "Efficiency kitchen" Sec. 26-02-140)
  • Has a separate exterior entrance.
  • Private or shared bathroom okay.
  • No extra parking required!
  • May be rented, but no short-term rental is allowed.

Accessory Dwelling Units vs. Junior Accessory Dwelling Units

Find out which situation applies to your property.



Junior accessory dwelling units are allowed within an existing single-family dwelling in the following zoning districts.

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  • Junior units may be rented separately.
  • Junior units may not be rented on a transient occupancy basis (less than 30 days), so they cannot be used as vacation rentals.
  • The owner must live in the house or junior unit. This does not apply if the house is owned by a public agency, land trust, or non-profit housing organization.
  • A junior unit must be installed after construction of the single family dwelling.
  • One junior unit is allowed per parcel.

Permits and Fees


  • Most junior units require the following process:
    1. Come to Permit Sonoma to apply for a building permit with a Permit Technician.
    2. Fill out the deed restriction form (PDF: 107 kB). Please bring your Legal Description (description of the parcel from your deed) with you to allow same-day recordation of the deed restriction.
    3. Go to the Planning station to obtain a Planner signature on the deed restriction.
    4. Have the deed restriction notarized (some Permit Sonoma staff can notarize).
    5. Go to the County Recorder's office to record the deed restriction.
    6. Return to Planning station at Permit Sonoma with the recorded deed for Planning sign off.
    7. Meet with Permit Sonoma staff at remaining stations for building permit issuance.
  • Junior units are not separate dwelling units and don’t require building or fire code upgrades or separate utility connections.
  • Junior units must be connected to a septic system or the sewer.

BPC-057 2016 CALGreen Checklist Residential Additions and Alterations (PDF: 216 kB)


Required Fees: Junior units are not required to pay development impact fees such as traffic and parks. However, other permit fees such as building permits will be required.

Contact Information

Contact Planning by Phone
Monday – Friday
10:00 AM – 12:00 PM
1:00 PM – 3:00 PM
2550 Ventura Avenue
Santa Rosa, CA 95403
38.465074, -122.723705


ADU Calculator

Junior Unit

Try this new online tool to help estimate the costs, returns, and benefits associated with building an ADU.

Fire Prevention & ADUs

Fire Prevention Information on Accessory Dwelling Units

Fire Prevention and HazMat

Requirements for ADUs including fire access, sprinklers, and more.

Sonoma County Housing Authority

Resources for Property Owners

Hands forming house

If you plan to rent your ADU, consider participating in the Housing Authority's Housing Choice Voucher program and being a part of the solution to the County's affordable housing crisis.

State ADU Law

California Department of Housing and Community Development's web site describing state laws and regulations about Accessory Dwelling Units.

View State Web Site