Sebastopol Municipal Code Ch. 17.220 Accessory Dwelling Units

This chapter provides for accessory dwelling units (ADU) and junior accessory dwelling units (JADU) consistent with California Government Code Sections 66310 to 66342. (Ord. 1162 § 2 (Exh. F), 2026; Ord. 1129 Exh. A § 6, 2019; Ord. 1111, 2018)

A. Location. Accessory dwelling units may be allowed as follows:

1. Parcels zoned for single-family, duplex or multifamily use, or on nonresidentially zoned properties, which are currently used for a single-family or multifamily residential use, either simultaneous to or subsequent to construction of the primary dwelling or dwellings;

2. Parcels which are currently used for a multifamily land use, when the accessory dwelling unit is created within portions of the existing multifamily dwelling structure that is not used as livable space, and if each space complies with applicable building and health and safety codes. However, one-story detached accessory dwelling units may be allowed on a multifamily dwelling parcel provided such units comply with the development standards for one-story accessory dwelling units in subsection D of this section;

3. 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.

1. Single-Family Residential Uses. This section shall allow the creation of any of the following units, or any combinations of the following units:

a. One ADU created within the proposed space of a single-family dwelling or existing space of a single-family dwelling or accessory structure; a 150-square-foot expansion to an existing accessory structure must also be permitted to accommodate ingress and egress.

b. One JADU created within the proposed space of a single-family dwelling or existing space of a single-family dwelling; JADU complies with requirements of California Government Code Section 66333.

c. One detached, new construction ADU with a floor area of up to 800 square feet with four-foot side and rear setbacks and a height compliant with California Government Code Section 66321(b).

2. Multifamily Residential Uses.

a. Up to eight detached accessory dwelling units shall be allowed on a parcel zoned multifamily residential; provided, that the total number of ADUs does not exceed the number of existing units on the lot. On multifamily lots with a proposed multifamily dwelling, up to two detached ADUs shall be allowed. Up to one attached ADU is allowed for each four existing multifamily units.

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. Standards. 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:

1. Floor Area. The floor area of the accessory dwelling unit shall not exceed:

a. Parcels of 10,000 square feet or greater: 1,000 square feet.

b. All other parcels: 850 square feet for a studio or one-bedroom accessory dwelling unit, or 1,000 square feet for an accessory dwelling unit that provides for more than one bedroom.

2. Notwithstanding the maximum sizes in subsection (D)(1) of this section, an attached accessory dwelling unit shall not be restricted to less than 800 square feet. The floor area of an attached accessory dwelling unit shall not exceed 50 percent of the existing living area or 1,000 square feet, whichever is less, unless a larger size is permitted by subsection (D)(1) of this section.

3. Height.

a. A height of 16 feet for a detached accessory dwelling unit on a lot with an existing or proposed single-family or multifamily dwelling unit.

b. A height of 18 feet for a detached accessory dwelling unit on a lot with an existing or proposed single-family or multifamily dwelling unit that is within one-half of one mile walking distance of a major transit stop or a high-quality transit corridor, as those terms are defined in Section 21155 of the Public Resources Code. An additional two feet in height is allowed if needed to accommodate a roof pitch on the accessory dwelling unit that is aligned with the roof pitch of the primary dwelling unit.

c. A height of 18 feet for a detached accessory dwelling unit on a lot with an existing or proposed multifamily, multistory dwelling.

d. A height of 25 feet for an accessory dwelling unit that is attached to a primary dwelling. An additional two feet in height is allowed if needed to accommodate a roof pitch on the accessory dwelling unit that is aligned with the roof pitch of the primary dwelling unit.

4. Setbacks.

a. 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, except that a setback of no more than four feet from the side and rear lot lines shall be required for an attached ADU that is 800 square feet or smaller.

b. One-story accessory dwelling units (both attached and detached) shall have side and rear setbacks of not less than four feet.

c. No setback shall be required for an ADU or JADU created within an existing living area or accessory structure or an ADU created in a new structure in the same location to the same dimensions as an existing structure.

d. A setback of no more than four feet from the side and rear lot lines shall be required for an accessory dwelling unit that is constructed above an existing garage.

e. A front yard setback shall be the same as required for the primary dwelling, except that no front yard shall be applied which would preclude an ADU of at least 800 square feet from being built on the property.

5. Manufactured and Mobile Homes. Manufactured and mobile home accessory dwelling units that meet the requirements of State law shall be allowed; provided, that they are placed on a permanent foundation, have minimum roof pitch of 3:12, do not utilize metal or aluminum siding and adhere to the development standards set forth in this chapter.

6. Utility Connections. Separate utility connections (sewer, water, gas, electricity, telephone) are not required but may be provided at the request of the applicant if approved by the City Engineer. Water and sewer connections are subject to payment of applicable hook-up fees, as well as encroachment permit(s), if necessary.

7. Renting Accessory Dwelling Units. The rental of an accessory dwelling unit is allowed, but not required.

a. Accessory dwelling units on a single-family residential property authorized after July 1, 2017, may not be rented on a transient occupancy basis (less than 30 days), unless a conditional use permit for transient occupancy has been granted.

b. Accessory dwelling units on a parcel with existing multifamily dwelling uses may not be rented on a transient occupancy basis (less than 30 days).

8. Separate Entrance Required. The entry to an attached accessory dwelling unit shall be accessed separately and securely from the principal unit. A pathway connecting the entrance to the accessory dwelling unit to the parking area or street is recommended but not required. No passageway shall be required.

9. Applicable Codes. Accessory dwelling units must comply with applicable building, fire and other health and safety codes except that if fire sprinklers were not required for the main home, they shall not be required in the accessory dwelling unit. The construction of an ADU shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling.

10. Lot Coverage. Accessory dwelling units shall not be considered when calculating the maximum lot coverage allowed.

11. Parking.

a. Accessory dwelling units have no parking requirement and shall not have a separate driveway curb cut on the same property frontage.

b. When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit, no parking replacement spaces shall be required. Any other required on-site parking spaces shall be maintained for the principal unit, and may be located 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. The ministerial approval of the Planning Director, or designee, shall be required for all accessory dwelling units. The property owner shall file a completed building permit application, and pay all applicable fees for ministerial review. The completed application form shall include, but not be limited to, data on the floor space and height of the proposed unit, an accurately drawn site plan showing the location and size of all existing and proposed structures, the proposed accessory dwelling unit, setbacks, protected trees on the subject parcel and adjacent parcels, utility connections and vehicle parking if proposed.

F. Nonconforming Zoning, Building Code Violations, and Unpermitted Structures.

1. An accessory dwelling unit shall not be denied because of a nonconforming zoning condition, a building code violation, or an unpermitted structure that does not present a threat to public health and safety and is not affected by the construction of the accessory dwelling unit.

2. A permit for an unpermitted ADU or JADU shall not be denied for a violation of building standards unless the local agency makes a finding that correcting the violation is necessary to comply with structural safety requirements.

G. Accessory dwelling units are not considered in the calculation of density.

H. 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. Accessory dwelling units of 750 square feet or less shall not be subject to City impact fees but may be subject to school impact fees. Accessory dwelling units larger than 750 square feet may, as determined by the City Council by resolution, be subject to impact fees charged proportionately in relation to the square footage of the primary dwelling unit.

I. An accessory dwelling unit created under this chapter shall be maintained with the provisions of this chapter and shall not be destroyed or otherwise converted to any other use (including reverting to a portion of the primary residence) except with approval of the Planning Director. In considering such requests, the Planning Director shall consider the length of time such permit has been in force, the conditions of approval, the exceptions granted for the permit, and the impact on the City’s affordable housing supply. As a condition of termination, the Planning Director shall require the owner to pay the applicable impact fees and to make modifications to the property to: (1) comply with current building code requirements and (2) comply with current development standards in effect at the time of the request to terminate the use of the ADU. (Ord. 1162 § 2 (Exh. F), 2026; Ord. 1129 Exh. A § 6, 2019; Ord. 1116 § 6, 2018; Ord. 1111, 2018)

A. Purpose. This section implements Government Code Section 66342, as amended by Assembly Bill 1033 (2023) to allow the sale of individual accessory dwelling units in certain circumstances, described below, in accordance with Government Code Section 66342 and as may be further amended from time to time. Where there are inconsistencies, the Government Code shall control.

B. Requirement.

1. Permit Required. Pursuant to Government Code Section 66342, this section provides for the streamlined approval for conversion of existing or new accessory dwelling units (ADU) into condominiums. These condominiums shall be sold or otherwise conveyed separately from the primary residence only under the conditions outlined in this part and pursuant to Government Code Section 66341. No condominium conversion of a project shall be permitted in any district without first obtaining approval of a parcel map pursuant to the provisions of this title and SMC Title 16.

2. ADU Condominium Requirements. Subject to the provisions of this section, to achieve the purposes of this chapter, all projects shall conform to the following requirements:

a. Except as allowed by State law, all structures and buildings included as part of a condominium project shall conform to the building and zoning requirements applicable to the zoning district in which the project is proposed to be located. Designation of individual condominium units shall not be deemed to reduce or eliminate any of the building and zoning requirements applicable to any such buildings or structures.

b. The condominium shall be created pursuant to the Davis-Stirling Common Interest Development Act, Part 5 (commencing with Section 4000) of Division 4 of the Civil Code) and with all applicable objective requirements of the Subdivision Map Act (Division 2 commencing with Section 66410) and all other objective requirements of this section.

c. Prior to recordation of the initial or any subsequent modifications to the condominium plan, written evidence of the lienholder’s consent shall be provided to the county recorder along with a signed statement from each lienholder that states as follows:

(Name of lienholder) hereby consents to the recording of this condominium plan in their sole and absolute discretion and the borrower has or will satisfy any additional terms and conditions the lienholder may have.

d. An accessory dwelling unit may not be sold or otherwise conveyed separate from the primary residence except under the conditions outlined in this chapter and of SMC Title 16, or built by a qualified nonprofit corporation and would be sold to a qualified buyer. Prior to approval of a parcel map, a home or property owners’ association or similar entity shall be formed for any condominium project. The association shall, at a minimum, provide for the administration, management and maintenance of all common areas including landscaping, drive aisles and parking areas, maintenance of the exterior of all buildings, pool or common roof, the collection of dues, payment of public utilities not billed separately to each unit, and enforcement of standards within the project.

The owner of a property or a separate interest within an existing planned development that has an existing association, as defined in Section 4080 of the Civil Code, shall not record a condominium plan to create a common interest development under Section 4100 of the Civil Code without the express written authorization by the existing association.

For purposes of this subsection, “written authorization by the existing association” means approval by the board at a duly noticed board meeting, as defined in Section 4090 of the Civil Code, and if needed pursuant to the existing association’s governing documents, membership approval of the existing association.

e. If an accessory dwelling unit is established as a condominium, the homeowner shall notify providers of utilities, including water, sewer, gas, and electricity, of the condominium creation and separate conveyance.

f. The ADU shall comply with all applicable technical codes including the California Building and Fire Codes. Prior to approval of the parcel map, a safety inspection of the ADU shall be conducted as evidenced through issuance of a final building permit or a housing quality standards report from a building inspector certified by the United States Department of Housing and Urban Development. (Ord. 1162 § 2 (Exh. F), 2026)

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; or, as part of a proposed single-family residential use, including an attached accessory structure.

B. Limitation. In no case shall more than one junior accessory dwelling unit be placed on the same single-family lot or parcel.

C. Size. A junior accessory dwelling unit shall not exceed 500 square feet.

D. Occupancy. Owner-occupancy is required when the JADU shares a bathroom with the main dwelling 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.

E. Existing Structure/Bedroom. A junior accessory dwelling unit shall be located within the walls of an existing or proposed single-family residence including attached garages.

F. Entrance. A junior accessory dwelling unit shall include its own discrete entrance, separate from the main entrance to the structure. A permitted junior accessory dwelling unit may include an interior entry to the main living area, and may include a second interior doorway for sound attenuation.

G. Kitchen. The junior accessory dwelling unit shall include an all-electric efficiency kitchen, which shall include all of the following: sink, food preparation counter, refrigerator, and storage cabinets that are of reasonable size in relation to the size of the junior accessory dwelling unit.

H. Parking. Junior accessory dwelling units have no parking requirement.

I. 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:

1. 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

2. A restriction on the size and attributes of the junior accessory dwelling unit that conforms with this section.

J. No Transient Occupancy. A junior accessory dwelling unit shall not be offered for rent less than 30 days. Air B&B and vacation rentals are prohibited.

K. Timing. A permit shall be issued within 60 days of submission of an application for a junior accessory dwelling unit that meets the criteria in this section and is part of an existing single-family dwelling or attached garage.

L. 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.

M. 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.

N. A junior accessory dwelling unit created under this chapter shall be maintained with the provisions of this chapter and shall not be destroyed or otherwise converted to any other use (including reverting to a portion of the primary residence) except with approval of the Planning Director. In considering such requests, the Planning Director shall consider the length of time such permit has been in force, the conditions of approval, the exceptions granted for the permit, and the impact on the City’s affordable housing supply. As a condition of termination, the Planning Director shall require the owner to pay the applicable impact fees and to make modifications to the property to: (1) comply with current building code requirements and (2) comply with current development standards in effect at the time of the request to terminate the use of the JADU. (Ord. 1162 § 2 (Exh. F), 2026; Ord. 1129 Exh. A § 6, 2019; Ord. 1111, 2018)