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Differences Between ADUs, JADUs, and Guest Houses

Sonoma County allows several types of residential accessory structures (see Policy 1-4-6, Residential Accessory Structures for a complete list). Below is a summary of the differences between some of the most common--Accessory Dwelling Units (ADUs), Junior Accessory Dwelling Units (JADUs), and guest houses. 

Structure TypeAccessory Dwelling UnitJunior Accessory Dwelling UnitGuest House
StructureMay be attached to or detached from the main dwelling or accessory structureMust be created from, and within the footprint of, an existing single-family dwellingAccessory building to a single-family dwelling which consists of a detached living area of a permanent type of construction
KitchenMust have a full kitchen (see Policy 1-4-5, Definition of a Kitchen)Must have a small kitchenCannot have a kitchen or wet bar
BathroomMust have a full bathroomMust have direct access to a bathroom, either inside the unit or in the main houseMay have a half or full bath
Long-Term RentalCan be rentedCan be rentedCannot be rented or occupied separately from the main house.
Transient RentalMay not be used as a vacation rentalMay not be used as a vacation rentalMay be able to be used as part of a vacation rental or hosted rental with a zoning permit
Z Combining DistrictProhibited in the Z Combining DistrictAllowed in the Z Combining DistrictAllowed in the Z Combining District
Size Limit1,200 square feet500 square feet640 square feet
Permits RequiredBuilding permitBuilding permitBuilding permit
More InformationAccessory Dwelling UnitsJunior Accessory Dwelling Units1-4-6 Detached Residential Accessory Structures
Zoning Code Reference

Changes in State law took effect on January 1, 2020. As a result, local rules (Section 26-88-060 of the Sonoma County Zoning Ordinance) no longer apply. Current standards in State law are summarized on the County's ADU website.

Changes in State law took effect on January 1, 2020. As a result, local rules (Section 26-88-061 of the Sonoma County Zoning Ordinance) no longer apply. Current standards in State law are summarized on the County's JADU website

"Guest house" Sec. 26-02-140