ADU Building, Zoning, and Design Regulations for Santa Rosa, CA

Santa Rosa is a great place to build an ADU and allows you to add significant value to your property. Before you start building, make sure you understand Santa Rosa’s special use regulations for accessory dwelling units.


Santa Rosa ADU Zoning Requirements

Zoning Regulations:

  • One main dwelling unit and one accessory dwelling unit and one junior accessory dwelling unit may be allowed on any lot in a residential or mixed use zone where there is only one existing single family dwelling on the lot.
  • No more than two accessory dwellings in a new building detached from the existing buildings may be added to a lot that has an existing multifamily dwelling unit.
  • Attached and detached single-family ADUs may not cover more than 40% of the existing lot.

Setback Requirements for ADUs in Santa Rosa

Development standards for ADUs in Santa Rosa, including setbacks have been simplified and are listed below for single-family attached or detached ADUs. There are no setback requirements for conversion ADUs.

  • Front setback must be a minimum of 20 feet.
  • Side setbacks should be a minimum of 4 feet.
  • Corner setbacks must be at least 8 feet.
  • Rear setbacks should be no less than 4 feet.

Maximum Size

Maximum Area

  • Attached accessory dwelling units: An attached ADU is allowed up to 50% of existing residential square footage.
  • Detached accessory dwelling units: One and two story detached ADUs are allowed a maximum area up to 1,200 square feet.
  • Conversion ADUs: Up to 45% of existing residential square footage or 1,200 square feet, whichever is less.

Maximum Height

  • Single story ADUs are limited to a maximum height of 16 feet.
  • Maximum height for two story ADUs is 27 feet.

Santa Rosa ADU Rentals

To be used for rental purposes and as a source of passive income, accessory dwelling units and junior accessory dwelling units may only be rented in increments of 30 days or more. Neither an ADU nor a JADU can be rented for periods of less than 30 days.


Parking Requirements for ADUs in Santa Rosa

For any new detached ADU, one (1) additional parking space is required; however, no parking is required if:

  • The ADU is 750 square feet or less or a studio unit
  • The property is located in a historic preservation district
  • The property is within 0.5 miles of a transit stop
  • The ADU is part of the existing residence or within an existing accessory structure
  • When on-street parking permits are required but not offered to the occupant of an ADU
  • The property is within one block of a car-share vehicle.

For an internal conversion ADU or for a JADU, additional parking is not required.

View All Santa Rosa ADU Regulations

Custom ADU Builder in Santa Rosa

Backyard Unlimited has helped our Santa Rosa neighbors increase their liveable space and property values by adding accessory dwelling units to their properties.

Over the years, we have worked throughout the greater Santa Rosa area, installing ADUs and backyard structures in Vallejo, Napa, and Sonoma.
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