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State Law

Accessory Dwelling Units (ADUs)

Formerly known as “second dwelling units” or “granny units,” the current term is Accessory Dwelling Units. State law has removed barriers to Accessory Units for the purpose of encouraging creation of more affordable housing statewide. The laws make Accessory Dwelling Unit permits cheaper and easier to get by preventing local agencies from requiring separate water and sewer connections in converted units, by limiting the review period to a maximum of 120 days, and by removing the minimum parcel size requirement.

Junior Accessory Dwelling Units (JADUs)

State law also allows cities and counties to permit a new type of housing called a “Junior Accessory Dwelling Unit.”

Together, these laws reduce physical and financial barriers to creating accessory dwelling units which support the “Housing First Model” adopted by both the State and Sonoma County.

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

Housing Initiatives

Permit Sonoma Housing Initiatives

Housing Initiatives

Permit Sonoma is introducing several initiatives to help meet the County's housing production goals.