Chapter 21.74 — ACCESSORY DWELLINGS

The purpose of these regulations is to provide clearly stated land use regulations and development standards that allow for the development of accessory dwellings in compliance with applicable state regulations and local land use policy.

These regulations are intended to encourage the development of accessory dwellings providing for an expanded variety of housing opportunities for all income levels while retaining compatibility with surrounding uses and, when located within an agricultural zoning district, promoting the continued conservation of agricultural resources.

(Ord. CS 1290 §20, 2021)

The regulations set forth in this chapter shall apply to the permitting of accessory dwelling units and junior accessory dwelling units consistent with the requirements of state law. Accessory dwellings and junior accessory dwellings are permitted in all residential zones including the R-1 (Low Density Residential), R-2 (Medium-Density Residential), R-3 (Multi-Family Residential), R-A (Rural Residential), Mixed-Use (MU), and A-2 (General Agriculture) districts. These regulations shall also apply in all Planned Development (P-D) zoning districts permitting residential uses.

• A. When located within a local agency formation commission (LAFCO) adopted sphere of influence (SOI) of a city, accessory dwellings and junior accessory dwellings shall be permitted consistent with any applicable regulations of that city, provided said standards are consistent with state law.

• (Ord. CS 1290 §20, 2021; Ord. CS 1408, 12/9/2025)

The following general standards shall apply to accessory dwellings permitted by this chapter:

• A. Number of units, subject to the exceptions listed below and to the applicable general and development standards of this chapter, except as preempted by state law.

  1. The total number of accessory dwellings permitted per parcel with only single-family dwelling(s), existing or proposed, as permitted by the applicable zoning district, shall be limited to the following:

     • a. One junior accessory dwelling when located within the space of or attached to a proposed or existing single-family dwelling; and

     • b. One detached or attached accessory dwelling.

  2. The total number of accessory dwellings permitted per parcel with any existing or proposed two-family dwelling (duplex), as permitted by the applicable zoning district, shall be limited to the following:

     • a. One junior accessory dwelling when located within the space of or attached to a proposed or existing duplex; and

     • b. Two detached accessory dwellings.

  3. The total number of accessory dwellings permitted per parcel with any existing or proposed multi-family dwelling, as permitted by the applicable zoning district, shall be limited to the following:

     • a. Attached Accessory Dwellings. Up to twenty-five percent of the existing or proposed number of dwelling units may be developed within an existing multi-family dwelling provided that any permitted accessory dwelling(s) is located within the portions of the multi-family dwelling that are not currently used as livable space, including, but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages; and

     • b. Detached Accessory Dwellings.

       • i. Existing Multi-Family Dwelling. One detached accessory dwelling per existing multi-family dwelling, up to a maximum of eight per parcel; or

       • ii. Proposed Multi-Family Dwelling. Up to two detached accessory dwellings.

  4. Exceptions.

     • a. Where a parcel has a combination of single-family, two-family (duplex) or multi-family dwellings, as permitted by the applicable zoning district, accessory dwellings shall be

limited to the number permitted by Section 21.74.030.A.2 of this chapter.

  - b. Where a parcel contains more units than are permitted by the applicable zoning district, the parcel shall be limited to Section 21.74.030.A.1.a. 

  - c. In the A-2 Zoning District. On parcels of twenty acres or more, one accessory dwelling unit is permitted in lieu of a second dwelling when there is only one single-family dwelling on the parcel. Where a parcel of any size is already developed with more dwellings than permitted by the zoning district, no accessory dwelling unit shall be permitted. Up to one junior accessory dwelling per parcel shall be permitted. 

  - d. No accessory dwelling unit or junior accessory dwelling shall be permitted on any parcel that is developed with a dwelling or other use that is not in compliance with this Title or Title 16 of the County Code. 

• B. Accessory dwellings shall meet the following criteria:

1. The maximum square footage of a new accessory dwelling shall not exceed one thousand two hundred square feet of living space, or five hundred square feet of living space for a junior accessory dwelling, except for temporary mobile homes being converted to permanent status in accordance with Chapter 21.72 of this title. Any replacement of the mobile home shall comply with the maximum square footage requirements of this chapter at the time of replacement.

   2. The accessory dwelling shall have a separate entrance and no shared living space, or connecting interior access, with the main dwelling, unless the unit meets the definition of a junior accessory dwelling.

   3. The accessory dwelling shall be constructed concurrent with or subsequent to the main dwelling.

• C. Location. Detached accessory dwellings shall be placed to take maximum advantage of existing facilities including utilities and driveways. New driveways may be authorized in accordance with subsection F of this section.

  1. In the A-2 zoning district, an accessory dwelling shall be located within one hundred fifty feet of the main dwelling and shall not displace any area used for agricultural crop production. Any accessory dwelling unit not meeting these location standards may be permitted by staff approval permit when, in addition to the findings required under Section 21.100.030(A) of this title, the planning director determines that the location of the accessory dwelling unit is by design accessory to the main dwelling and will not interfere with the continued agricultural use of the parcel.

• D. Mobile Homes. A mobile home may be utilized in lieu of a detached accessory dwelling, provided the mobile home meets the requirements of this chapter and the eligibility and compatibility criteria included in Section 21.72.020 of this title.

• E. Water Supply and Wastewater Disposal. All accessory dwellings shall comply with all applicable local and state requirements for water supply and wastewater disposal, including, but not limited to, Section 21.08.050 requirements of this title.

• F. Access. Access to the accessory dwelling shall be in conformance with adopted County Fire Code and Public Works Standards and Specifications. Where access does not meet current standards, including street and alley access, access may be approved when the fire warden and the director of public works both find that public safety will not be negatively impacted.

• G. Fire Hazard Severity Zones. Accessory dwellings located in very high and high fire hazard severity zones, as designated by the most current California Department of Forestry and Fire Protections Fire Hazard Severity Zone Maps, shall meet current Fire Code standards.

• H. Williamson Act Contracted Lands. Accessory dwellings permitted under this chapter shall be allowed on Williamson Act Contracted Lands provided the accessory dwelling does not interfere with the continued agricultural use of the parcel in accordance with subsection (C)(1) of this section.

• (Ord. CS 1290 §20, 2021; Ord. CS 1408, 12/9/2025)

Accessory dwellings developed in accordance with this chapter shall meet the development standards outlined in this section, in addition to any other applicable development standards for Title 21 . Where a conflict may arise, the provisions of this section shall govern. The following development standards shall be met:

• A. Height. Maximum height shall be the same as specified for dwellings in the applicable zoning district.

• B. Setbacks. Accessory dwellings shall comply with the setback requirements of the applicable zoning district with the following exceptions:

  1. A minimum setback of four feet from the side and rear lot lines shall be required for new construction.

  2. No additional setbacks shall be required when an existing, legally established, garage or other existing residential accessory building is converted to an accessory dwelling in accordance with the provisions of this section.

• C. Parking. The following parking requirements shall apply to all accessory dwellings:

  1. One off-street parking space shall be required for every accessory dwelling, except no offstreet parking shall be required if any of the following apply:

     • a. An existing legally constructed accessory structure, including a garage or carport, is being converted into an accessory dwelling;

     • b. The accessory dwelling is located within a half mile from a public transit stop, including, but not limited to, a bus stop or train station, where the public may access buses, trains, subways, and other forms of transportation that charge set fares, run on fixed routes, and are available to the public;

     • c. The accessory dwelling is located in an area where on-street parking permits are required, but not offered to the occupant of the accessory dwelling; or

     • d. The accessory dwelling is located within one block of a designated car share/commuting pick up area; or

     • e. The unit is a junior accessory dwelling.

  2. All required off-street parking facilities shall be developed in accordance with the standards of the county department of public works.

• D. Density. An accessory dwelling that conforms to the requirements of this chapter shall be deemed a residential accessory use and will not be considered to exceed the allowable density for the parcel as established by the Stanislaus County General Plan or this title.

E. Lot Coverage. Lot coverage limits shall not apply to the development of accessory dwellings. (Ord. CS 1290 §20, 2021; Ord. CS 1408, 12/9/2025)

§ 21.74.050. Restrictive covenant.

Before obtaining a building permit for an accessory dwelling, the property owner shall sign, and provide the necessary recording fees, and the county shall file with the county recorder, a restrictive covenant acknowledging that:

• A. Except as otherwise preempted by state law, an accessory dwelling or junior accessory dwelling may not be sold or otherwise conveyed separately from the parcel on which it is located, or from any dwelling, on that parcel. Any future land division shall be subject to all applicable Stanislaus County subdivision requirements and regulations in effect at the time a land division is proposed and may include conversion of the accessory dwelling to a main dwelling as permitted by the applicable zoning district.

• B. Any modification to the accessory dwelling shall comply with all applicable provisions of this title for accessory dwellings, as such provisions may be amended from time to time.

• C. The rental of the accessory dwelling or junior accessory dwelling shall be for a term longer than thirty days.

• D. The limitations set by this chapter shall be binding upon any assigns, successors in interest, personal representatives, estates, and heirs of the owner of any property which includes accessory dwellings or junior accessory dwellings.

• (Ord. CS 1290 §20, 2021; Ord. CS 1408, 12/9/2025)