Chapter 17.220 — ACCESSORY DWELLING UNITS
Sebastopol Zoning Code · 2026-06 edition · ingested 2026-07-07 · Sebastopol
17.220.010 Purpose. ¶
This chapter provides for accessory dwelling units and junior accessory dwelling units consistent with Government Code Section 65852.2.
17.220.020 Accessory dwelling unit criteria. ¶
A. Location. Accessory dwelling units may be allowed only on parcels zoned for single-family, duplex or multifamily use, or on non-residentially zoned properties which are currently used only for a single-family residential use, either simultaneous to or subsequent to construction of the principal single-family detached dwelling. In addition, an existing dwelling unit that complies with the development standards for accessory dwelling units in subsection D. of this section may be considered an accessory dwelling unit, and a new principal unit may be constructed, which would then be considered the principal dwelling unit.
B. Limitation. In no case shall more than one accessory dwelling unit be placed on the same lot or parcel.
C. All requirements and regulations of the district in which the lot is situated shall apply, except as set forth in subsection D. of this section.
D. Conditions. The accessory dwelling unit may be established by the conversion of an attic, basement, garage or other portion of an existing residential unit or by new construction; a detached accessory dwelling unit may be established by the conversion of an accessory structure or may be established by new construction provided the following criteria are met:
- Floor Area. The floor area of the accessory dwelling unit shall not exceed:
a. Parcels of 10,000 sq. ft. or greater: 1,000 square feet.
b. All other parcels: 840 square feet.
The increased floor area of an attached accessory dwelling unit shall not exceed 50% of the existing living area.
Height. The height of a one-story detached accessory dwelling unit shall not exceed 17 feet, and a detached two-story accessory dwelling unit shall not exceed 25 feet.
Architecture. Accessory dwelling units shall be substantially compatible with the principal unit and the neighborhood.
Setbacks. Two-story accessory dwelling units and accessory dwelling units attached to the primary residence shall be subject to the same minimum side, front, and rear setback requirements as the primary residence. Detached one-story accessory dwelling units shall be subject to one-half of the primary residence side and rear setbacks, but not less than five feet. However:
- a. No setback shall be required for a garage existing as of July 1, 2017 that is converted to an accessory dwelling unit, and a setback of no more than five feet from the side and
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rear lots line shall be required for an accessory dwelling unit that is constructed above a garage.
Manufactured and Mobile Homes. Manufactured and mobile home accessory dwelling units, as that meet the requirements of State law, shall be allowed, provided that they are constructed on a permanent foundation, are deemed substantially compatible architecturally with the principal unit by the Planning Director, and adhere to the development standards set forth in this chapter.
Utility Connections. At the discretion of the City Engineer, utility connections (sewer, water, gas, electricity, telephone) may or may not be connected to the principal dwelling unit. If utility connections are separate from the principal unit, power and telephone lines shall be underground from the point of source as approved by the respective utility purveyor to the accessory dwelling unit. However:
- a. For the creation of an accessory dwelling unit contained within the existing space of a single-family residence or accessory structure the City shall not require the applicant to install a new or separate utility connection directly between the accessory dwelling unit and the utility or impose a related connection fee or capacity charge.
Selling Accessory Dwelling Units. The accessory dwelling unit shall be not offered for sale apart from the principal unit.
Renting Accessory Dwelling Units. The rental of an accessory dwelling unit is allowed, but not required.
- a. Accessory dwelling units authorized after July 1, 2017 may not be rented on a transient occupancy basis (less than thirty (30) days), unless a conditional use permit for transient occupancy has been granted.
- Separate Entrance Required. The entry to an attached accessory dwelling unit shall be accessed separately and securely from the principal unit.
- a. No passageway shall be required in conjunction with the construction of an accessory dwelling unit. For the purpose of this chapter, a passageway is pathway that is unobstructed clear to the sky and extends from a street to one entrance of the accessory dwelling unit.
Applicable Codes. Accessory dwelling units must comply with applicable building, fire and other health and safety codes.
Lot Coverage. Accessory dwelling units shall not be considered when calculating the maximum lot coverage allowed.
Parking.
a. No parking requirement shall apply.
b. When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit, the replacement space may be located
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in any configuration on the same lot as the accessory dwelling unit, including, but not limited to, as covered spaces, uncovered spaces, or tandem spaces, or by the use of mechanical automobile parking lifts.
E. Application Procedure. Planning Director approval shall be required for all accessory dwelling units. The property owner shall file a completed administrative review application with the Planning Department and pay all applicable fees. The completed application form shall include, but not be limited to, data on the floor space and height of the proposed unit and the existing residential unit(s), a photograph of the existing residential unit(s), the height of adjacent residences, and an accurately drawn site plan showing the location and size of all existing and proposed structures, the proposed accessory dwelling unit, setbacks, utility connections and vehicle parking.
de, but not be limited to, data on the floor space and height of the proposed unit and the existing residential unit(s), a photograph of the existing residential unit(s), the height of adjacent residences, and an accurately drawn site plan showing the location and size of all existing and proposed structures, the proposed accessory dwelling unit, setbacks, utility connections and vehicle parking.
F. Conversion of Existing Structures into Accessory Dwelling Units. Subject to the approval of the Planning Director, in the case of the conversion of a non-garage one-story building legally constructed prior to October 19, 2004, the rear setback shall conform to the setback requirement for an accessory building; however, the structure is not required to meet the side yard setback if nonconforming. In acting on such an application, the Planning Director may impose conditions requiring physical changes in the unit to ensure conformance to physical development standards.
G. Existing Non-permitted Accessory Dwelling Units. The Planning Director may approve an accessory dwelling unit constructed without benefit of required permits; provided, that the unit conforms to the current building code, is subject to applicable current permit and impact fees, and conforms to setback, height, area, and other physical development standards otherwise applicable.
H. Accessory dwelling units shall not be counted as “development units” under the General Plan density requirements.
I. Accessory dwelling units shall not be considered new residential uses for the purposes of calculating local agency connection fees or capacity charges for utilities, including sewer and water.
J. If the accessory dwelling unit is contained within the existing space of a single-family residence or accessory structure, has independent exterior access from the existing residence, and the side and rear setbacks are sufficient for fire safety, said accessory dwelling unit shall not be required to provide fire sprinklers if they are not required for the primary residence (unless otherwise required by the Fire Chief based on State law). This only applies to development inside of existing residences or accessory structure conversions.
17.220.030 Junior accessory dwelling unit criteria. ¶
A. Location. Junior accessory dwelling units may be allowed only on parcels zoned for single-family residential use with an existing single-family dwelling unit on the parcel.
B. Limitation. In no case shall more than one junior accessory dwelling unit be placed on the same lot or parcel.
C. Occupancy. Owner-occupancy is required in the single-family dwelling unit in which the junior accessory dwelling unit will be permitted. The owner may reside in either the remaining portion of the single family dwelling unit or the newly created junior accessory dwelling unit. Owneroccupancy shall not be required if the owner is a governmental agency, land trust, or housing organization.
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D. Existing Structure/Bedroom. A junior accessory dwelling unit shall be located within the existing walls of the structure and requires the inclusion of an existing bedroom.
E. Entrance. A junior accessory dwelling shall include its own discrete entrance, separate from the main entrance to the structure, with an interior entry to the main living area. A permitted junior accessory dwelling may include a second interior doorway for sound attenuation.
F. Kitchen. The junior accessory dwelling unit shall include an efficiency kitchen, which shall include all of the following:
A sink with a maximum waste line diameter of 1.5 inches.
A cooking facility with appliances that do not require electrical service greater than 120 volts, or natural or propane gas.
A food preparation counter, refrigerator, and storage cabinets that are of reasonable size in relation to the size of the junior accessory dwelling unit.
- G. Parking. No parking requirement shall apply.
H. Deed Restriction. The junior accessory dwelling unit shall not be offered for sale apart from the principal unit. A deed restriction, which shall run with the land, shall be filed with the City and shall include both of the following:
A prohibition on the sale of the junior accessory dwelling unit separate from the sale of the single-family residence, including a statement that the deed restriction may be enforced against future purchasers; and
A restriction on the size and attributes of the junior accessory dwelling unit that conforms with this section.
I. Timing. A permit shall be issued within 120 days of submission of an application for a junior accessory dwelling unit that meets the criteria in this section.
J. For the purposes of any fire or life protection ordinance or regulation, a junior accessory dwelling unit shall not be considered a separate or new dwelling unit.
K. For the purposes of providing service for water, sewer, or power, including a connection fee, a junior accessory dwelling unit shall not be considered a separate or new dwelling unit.
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