Accessory Dwelling Units

***Note: 2020 State Law Impacts on Existing Ordinance***

(Last update: November 27, 2019)
In light of recent state Accessory Dwelling Unit legislation, the existing Santa Rosa Accessory Dwelling Unit Ordinance requires amendments. City staff members are currently preparing an updated Ordinance to comply with State law. 

The following State bills address Accessory Dwelling Units and are effective beginning January 1, 2020.

Assembly Bill 68

Senate Bill 13

Assembly Bill 881

Additional updates and resources will be posted to the webpage as they become available.

Zoning Code Revisions

On December 12, 2017, and October 2, 2018, the City Council adopted ordinances amending the Accessory Dwelling Unit (ADU) section of the Santa Rosa Zoning Code in compliance with State law and in support of the City's Housing Action Plan.

The ordinances were incorporated into Zoning Code Section 20-42.130 (Accessory Dwelling Units) .

Fee Reductions

Development Impact Fees

Certain development impact fees for ADUs have been reduced.  The mount to be paid for each of the following fees is identified in the chart below:

  • Capital Facilities fees
  • Parks fees

Unit Size (Square Feet)

Percentage of Impact Fees Assessed

(the % of the fee to be paid by the applicant)

Larger Than

Up To

Internal Conversion











Utility Connections and Fees

Pursuant to Zoning Code Section 20-42.130(D)(3)(b), no new or separate utility connection, or related connection fee or capacity charge, will be required for the following ADUs: 

  • Internal conversions of existing space within a single-family residence or an accessory structure; or 
  • New ADUs (detached or attached) that are 750 square-feet or smaller.

Frequently Asked Questions

The following are answers to frequently asked questions related to Accessory Dwelling Units (ADU) and Junior Accessory Dwelling Units (JADU):

What is an ADU?

An Accessory Dwelling Unit (ADU) is an attached or detached residential dwelling, located on the same parcel as an existing single-family dwelling, that provides complete independent living facilities, including sleeping, cooking, bathing,and sanitation. An ADU can be located on any property where the zoning district allows single-family residential by right, and on any parcel that already contains only one single-family residence.

What is a JADU?

A Junior ADU (or JADU) is a new category of dwelling unit created by the State of California and adopted by the City of Santa Rosa. There are several distinctions between a standard ADU and a JADU detailed in the table below. The main difference is that a JADU is not required to have a dedicated bathroom.

Maximum Unit SizeYes. Generally up to 1,200 square feet or 50% of living area.Yes. 500-squarefoot maximum.
BathroomYes.No. Common sanitation allowed.
Separate EntranceDepends.Yes.
ParkingDepends. Parking may be eliminated and cannot be required under specified conditions.No. Parking cannot be required
Owner OccupancyDepends. Owner occupancy may be requiredYes. Owner occupancy is required.
Ministerial Approval ProcessYes.Yes.
Prohibition on Sale of ADUYes.Yes.

What are the building permit application submittal requirements?

The following are the materials required for submittal of a building permit for both an ADU and JADU:

  • Site plan
  • Floor plan 
  • Foundation plan
  • Interior cross sections
  • Construction details
  • Elevations for new structures
  • Photographs of site for new structures
  • Materials and color board for new structures
  • Deed Restriction or affordability contract as applicable (see the owner occupancy information below)
  • Historic Resource Survey as applicable (see the historic preservation district information below)

Building Division staff have prepared checklists for design professionals to ensure a complete submittal and minimize the need for plan revisions and related delays.  They are linked below:

Will my ADU require fire sprinklers?

Although state legislation exempts many ADUs from fire sprinklers, there are other instances where factors may still require the installation of fire sprinklers. Three of these factors are:

  1. Distance for fire response and access during emergency operations. Fire sprinklers may be required if any portion of the ADU is greater than 150 feet from Fire Department access (usually the street or road).
  2. Distance to fire suppression water supply. Fire sprinklers may be required If any portion of the ADU is greater than 400 feet from a water supply (typically a fire hydrant).
  3. ADU over a garage or carport. Fire sprinklers are required throughout a garage or carport with habitable space above. Garage or Carport AND an ADU require sprinklers.

NOTE: There may be additional factors that can require the installation of fire sprinklers.

Please be sure to check with Santa Rosa Fire to determine the need for fire sprinklers. Fire Department personnel are available at Planning & Economic Development on Tuesdays and Thursdays from 10:00AM to 12:00PM.

The Fire Department Plan Review Division can be reached at (707) 543-3524 or

How do I obtain a permit for an existing Accessory Dwelling Unit?

Planning Department staff has prepared an informational handout to guide applicants through the process available HERE

If my property is located in one of the City's historic preservation districts, do I need to apply for a Landmark Alteration Permit?

No, a Landmark Alteration Permit is not required for ADUs or JADUs.  However, through photographs, color and materials boards, architectural elevations and other means, you will be required to demonstrate that the proposed ADU is consistent with the time period of the residence's construction and/or the adjacent historic structures.

Please note, for properties that are identified as a contributor to the preservation district in which they are located, a historic resource survey, prepared by a qualified professional, will be required.  To determine if your property is a contributor, please contact Planning staff.

Does my property need to be owner occupied?  

Yes, either the main residence on the site or the ADU must be occupied by the property owner.  Prior to occupancy of an ADU or JADU, the property owner is required to file with the County Recorder a deed restriction as out lined in Zoning Code Section 20-42.130(G), which addresses owner occupancy of one of the units on site.

However, in lieu of the owner-occupancy restriction, the property owner may execute an affordability contract with the Department of Housing and Community Services, requiring the rental of one of the units on the property to low income households at restricted rents. See Zoning Code Section 20-42.130(H).  

Housing Department staff has prepared an informational handout on affordability contracts available HERE.

Instructions on processing a deed restriction without an affordability contract are available HERE.

Instructions on processing a deed restriction with an affordability contract are available HERE.

For more information on the affordability contract, please contact Nancy Manchester at (707) 543-4339 or

Can I rent my ADU or JADU out as a vacation rental unit?

Neither an ADU nor a JADU cannot be rented for periods of less than 30 days.

Do I need to provide parking for my ADU or JADU?

The following outlines the parking requirements for both ADUs and JADUs:

 Unit Type Number of Parking Spaces Required
 ADU – New Detached Unit  1 additional parking space is required 

With the following exceptions - no additional parking is required if one or more of the following exist:

  • The ADU is 750 square feet or less; or
  • The property is located in a historic preservation district; or 
  • The property is within 1/2 mile of a transit stop; or 
  • The property is within one block of a car-share vehicle.
 ADU – Internal Conversion No additional parking required
 JADU No additional parking required

If I convert my garage to an ADU, will I be required to replace those parking spaces on site?

Yes, if you convert a portion, or all, of your garage into an ADU you will be required to place the lost parking space, or spaces.  

However, if your property is located either within 1/2 mile of a transit stop, or one block from a car-share vehicle, then you will not be required to replace the lost space(s).

What are the development standards (setbacks, height, etc) for an ADU?

The following chart provides general development standards for ADUs.  Please note, setback requirements may vary depending on the property's zoning district.  The guide to the City's online mapping resources will help property owners determine their zoning district.  

The development standards for a main residence and accessory structure by zoning districted are depicted in Table 2-4 of the Zoning Code.  If the property is located in a Planned Development zoning district, please contact Planning Division staff to determine setbacks.  Other site constraints, such as easements or scenic road setbacks may apply.   


ADU Internal Conversion

ADU Residential Addition


1-story ADU

Detached 2-story ADU

Front Setback

Sufficient for fire safety as determined by Santa Rosa Fire Department

Same as Main Residence and determined by zoning district

20 feet

Same as Main Residence and determined by zoning district

Side – Interior Setback

5 feet (1)

Side – Corner Setback

15 feet (2)

Rear Setback

5 feet (1)

Height Limit


35 feet

16 feet

27 feet

Lot Coverage


Maximum Square Footage

Conversion of residence:

Up to 45% of existing residential square footage or 1,200 square feet, whichever is less


Conversion of detached accessory structure:

Up to 1,200 square feet

Up to 50% of existing residential square footage or 1,200, whichever is less

Up to 1,200 square feet

Up to 1,200 square feet


(1)  The side and rear setbacks for properties in hillside areas (properties with a slope of 10% or greater) shall observe a 15-foot setback from the side and rear property lines.

(2)  The corner setback in Rural Residential zoning designation is 20 feet.

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