New Laws Affecting Second Dwelling Units

March 24, 2017

Second Dwelling Units and Guest House Regulation Changes


What Has Changed?


In September 2016, three laws were signed by Governor Brown and included Senate Bill 1069, Assembly Bill 2406, and Assembly Bill 2299. These laws went into effect in the very recent past and have to do with the creation of second dwelling units. The term second dwelling unit is being replaced with accessory dwelling units and junior accessory dwelling units. To comply with these new State laws, the County of Sonoma passed Ordinance No. 6191. The County’s ordinance provides local compliance and is consistent with the Sonoma County General Plan. The ordinance shall be followed by individuals intending to develop accessory dwelling units and junior accessory dwelling units. 

Permits Required for Accessory Dwelling Units

Development of an accessory dwelling unit requires a zoning permit from the County of Sonoma and compliance with all applicable codes (building, fire, septic, water, etc.). Junior accessory dwelling units will not require a zoning permit or compliance with most codes, and only a building permit is required, as the junior accessory dwelling units are typically considered a portion of an existing residence that is being converted.

What Sizes Can Accessory Dwelling Units Be?

Junior accessory dwelling units cannot exceed 500 square feet in size and must be contained within the walls of an existing legal dwelling. The junior accessory units can have a kitchen facility and may share bathrooms with other units. Accessory dwelling units cannot exceed 1000 square feet in size and cannot be larger in size than the main dwelling unit. Accessory dwelling units can be detached from the main dwelling unit. 

We Can Help!

If you’re planning to develop an accessory dwelling unit, contact BC Engineering Group, we know the applicable laws and ordinances, and have extensive experience with these units. For more details about accessory dwelling units and the new regulations, please contact BC Engineering Group today at (707) 542-4321. Like us on 
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