Junior Accessory Dwelling Units

Junior Accessory Dwelling Units (JADUs) are small living units (up to 500 square feet) created from space within an existing single-family home. 

Note: Changes in State law took effect January 1, 2020, and as a result, local rules  (Sec. 26-88-061 of the Sonoma County Zoning Ordinance) no longer apply. New standards for JADUs are summarized below. 

Download a checklist summarizing current standards in State law

Compare Accessory Dwelling Units and Junior Accessory Dwelling Units

Updated ADU and JADU Ordinance Effective October 14, 2021

On September 14, 2021, the Sonoma County Board of Supervisors approved changes to the Zoning Code that updated ADU and JADU regulations. This page will be updated before the effective date of October 14, 2021. 

Read adopted ordinance (Ordinance No. 6352)

Summary of Standards

Below are some of the most common standards property owners need to know to plan for a JADU. For a complete list of development standards, please review the checklist above. 

  • Allowed in all zoning districts that allow single-family residences
  • Must be located within an existing or proposed single-family dwelling or attached garage
  • Maximum size of 500 square feet
  • Has a small kitchen
  • Has a separate exterior entrance
  • Private or shared bathroom
  • No extra parking required!
  • May be rented, but no short-term rental is allowed
  • Owner must reside in primary dwelling or JADU
  • One JADU per parcel (but may be on the same parcel as an ADU)

Permits and Fees


  • JADU will require a building permit to convert existing space to a dwelling unit.
  • A deed restriction form (PDF: 107 kB) must be recorded as follows: 
    1. You will need the legal description of your property (the description of the parcel from your deed). 
    2. Submit the form with the application for a building permit and a planner from the Planning Division will sign it and return it to you. Planning will place a hold on the final inspection pending receipt of the recorded form. 
    3. Have the form notarized. 
    4. Record the completed form with the County Recorder's office. Ask for a conformed copy. 
    5. Return the conformed copy to the Planning Division by email. 
  • JADUs don’t require fire code upgrades or separate utility connections.
  • JADUs must be connected to a septic or sewer system.


Development impact fees (traffic and parks) are not charged for JADUs. However, other fees associated with 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