Chapter 17.37
ACCESSORY DWELLING UNITS
Sections:
17.37.010 Purpose and definitions.
17.37.030 Occupancy and disposition.
17.37.050 Development regulations.
17.37.010 Purpose and definitions.
A. Purpose. It is the purpose of this chapter to provide for accessory dwelling units and junior accessory dwelling units as a form of potentially affordable housing. To ensure the public health, safety and general welfare of the community, this chapter establishes criteria to ensure that these units will conform to certain development standards.
B. Definitions. For the purposes of this chapter, the following terms shall be defined as follows:
1. “Accessory dwelling unit” or “ADU” is defined in CMC 17.04.025.
2. “Attached accessory dwelling unit” or “attached ADU” means an ADU that is constructed as a physical expansion of the primary dwelling and shares a common wall with the primary dwelling.
3. “Connection/capacity fee” means a fee charged for each new connection or expanded use of an existing connection to the water or sewer system based on the annual acre foot water requirements for each type of use as prescribed in Chapter 13.16 CMC (Resource Management System) and the standardized use table adopted by City Council resolution.
4. “Detached accessory dwelling unit” or “detached ADU” means an ADU that is constructed as a separate structure from the primary dwelling which does not share any walls with the primary dwelling.
5. “Development impact fee” or “impact fee” means a monetary exaction other than a tax or special assessment that is charged by the City to the applicant in connection with approval of a development project for the purpose of defraying all or a portion of the cost of public facilities related to the development project. It includes park and recreation fees under the Quimby Act. It does not include any connection fee or capacity charge.
6. “Junior accessory dwelling unit” or “JADU” is defined in CMC 17.04.387.
7. “Service lateral” means a physical pipe tie-in to the City-owned and operated water or sewer main.
8. “Water meter” means a City-owned device that records the quantity of water used by a customer. (Ord. 770 § 3, 2024; Ord. 744 § 2 (Exh. A), 2020).
17.37.020 Number of units.
A. One accessory dwelling unit (ADU) and one junior accessory dwelling unit (JADU) are permitted on a lot that is developed or is proposed to be developed with one one-family dwelling.
B. At least one ADU and up to 25 percent of the existing dwelling units are permitted within the portions of an existing multifamily dwelling structure that are not used as livable space. Each unit must comply with State building standards for dwellings.
C. Up to two ADUs are permitted on a lot that has an existing multifamily dwelling if they are detached from the multifamily dwelling.
D. ADUs and JADUs shall not be considered to exceed the density allowed by the applicable General Plan land use designation for the lot upon which it is located. (Ord. 744 § 2 (Exh. A), 2020).
17.37.030 Occupancy and disposition.
A. The property owner of a single-family residence with a JADU shall reside in one of the units, unless the owner is another governmental agency. land trust, or housing organization. The property owner shall also record a deed restriction, which shall run with the land and be filed with the City, and include both of the following provisions:
1. A prohibition on the sale of the JADU separate from the sale of the single-family residence, including a statement that the deed restriction may be enforced against future purchasers.
2. A restriction on the size and attributes of the JADU unit that conforms with this chapter.
B. Except as otherwise provided in California Government Code Section 66340 et seq., as may be amended from time to time, no ADU may be sold separately from the primary dwelling unit, and no subdivision of land or air rights is authorized by this chapter.
C. An accessory dwelling unit may be rented or leased; provided, that it is rented or leased for periods of 30 consecutive days or more. (Ord. 770 § 4, 2024; Ord. 744 § 2 (Exh. A), 2020).
17.37.040 Utilities and fees.
A. A newly constructed JADU/ADU shall be required to have either a separate or enlarged City-owned water meter, as determined by the City Engineer in accordance with City of Santa Rosa standards, American Water Works Association and other applicable standards, if the ADU is a new, detached structure or the JADU/ADU expands existing space by more than 150 square feet.
B. A newly constructed JADU/ADU shall be required to have a separate service lateral(s), as determined by the City Engineer in accordance with City of Santa Rosa standards, Uniform Plumbing Codes, and condition of existing sewer lateral if the ADU is a new, detached structure or the JADU/ADU expands an existing space by more than 150 square feet.
1. Even if a separate service lateral is not required, repairs to existing utility connections may be required when, in the opinion of the City Engineer, the existing lateral is substandard or lacks adequate capacity to serve the new JADU/ADU, creating a health and safety risk. To confirm the adequacy and safety of the existing lateral, the applicant shall provide the City Engineer with evidence confirming the existing lateral’s size and materials (e.g., photos of existing service laterals), hydraulic conditions (e.g., pressures and flows, slopes, and sizes), and CCTV footage (with Public Works staff present). The applicant is responsible for all costs related to providing this evidence to the satisfaction of the City Engineer.
C. Connection/capacity fees will be charged for a newly constructed JADU/ADU if it is a detached structure or if the JADU/ADU expands an existing space by more than 150 square feet. No connection/capacity fee will be charged for JADU/ADUs created through the conversion of existing space that do not expand the existing space beyond 150 square feet. If subject to a connection/capacity fee as described herein, the connection/capacity fee will be calculated as follows:
1. For JADU/ADUs subject to the connection/capacity fee but not constructed at the same time as a new single-family dwelling, the fee shall be proportionate to the burden of the proposed JADU/ADU upon the water or sewer system, based on either its square feet or the number of its drainage fixture unit (DFU) values, as defined in the Uniform Plumbing Code adopted and published by the International Association of Plumbing and Mechanical Officials. This fee shall not exceed the cost of providing this service.
2. For JADU/ADUs subject to the connection/capacity fee and constructed at the same time as a new single-family dwelling, the JADU/ADU shall be considered to be a new residential use for purposes of calculating connection/capacity fees.
D. Development impact fees shall not be charged for the development of a JADU of any size, or for an ADU that is less than 750 square feet. Any development impact fees charged for an ADU of 750 square feet or more shall be charged proportionately in relation to the square footage of the primary dwelling unit. (Ord. 770 § 5, 2024; Ord. 744 § 2 (Exh. A), 2020).
17.37.050 Development regulations.
A. Unit Size.
1. The floor area of a studio or one-bedroom ADU shall not exceed 850 square feet.
2. The floor area of an ADU with more than one bedroom shall not exceed 1,000 square feet.
3. The floor area of an ADU created through an addition to an existing primary dwelling unit may not exceed 50 percent of the primary unit’s existing living area.
4. An ADU or JADU created through the conversion of existing space may include an expansion of up to 150 square feet beyond the physical dimensions of the existing structure to accommodate ingress and egress to the unit.
B. Setbacks.
1. A newly constructed ADU shall maintain minimum rear and interior side yard setbacks of four feet.
2. No additional setback shall be required for an ADU that is created through the conversion of space in an existing primary dwelling unit or accessory structure, or for a structure constructed in the same location and to the same dimensions as an existing structure.
C. Height.
1. A height limit of 16 feet applies to a detached ADU on a lot with an existing or proposed single-family or multifamily dwelling unit. except as set forth below:
a. A height of 18 feet applies to a detached ADU on a lot with an existing or proposed single-family or multifamily dwelling unit that is within one-half mile walking distance of a major transit stop or a high-quality transit corridor, as those terms are defined in California Public Resources Code Section 21155. An additional two feet in height shall be permitted to accommodate a roof pitch on the detached ADU that has the same pitch of the primary dwelling unit.
b. A height limit of 18 feet applies to a detached ADU on a lot with an existing or proposed multistory multifamily dwelling.
2. An attached ADU shall not exceed the height limitation that applies to the primary dwelling unit or 25 feet, whichever is lower. This clause shall not be construed to permit an attached accessory dwelling unit to exceed two stories.
D. Lot Coverage.
1. The maximum coverage of a lot as provided in the applicable zoning district may be exceeded in order to allow the construction of at least an 800-square-foot ADU.
2. The maximum coverage of a lot as provided in the applicable zoning district may otherwise be exceeded as provided by CMC 17.38.050(C) in order to accommodate an ADU.
E. Parking.
1. Parking is not required for an ADU or JADU developed on a lot with an existing or proposed single-family primary dwelling.
2. When parking required by Chapter 17.36 CMC is displaced in conjunction with the construction of an ADU or a garage, carport or covered parking is converted to an ADU, the provision of replacement spaces is not required.
3. One parking space shall be provided for each ADU or JADU constructed as a separate structure on a lot with a multifamily primary dwelling, except as provided in subsection (E)(4) of this section. The parking may be located in required setback areas or through tandem parking unless specific findings are made that parking in setback areas or tandem parking is not feasible based upon specific site or regional topographical or fire and life safety conditions.
4. No off-street parking shall be required for the ADU in any of the following instances:
a. The ADU is located within one-half mile walking distance of a public transit stop.
b. The ADU is located within an architecturally and historically significant historic district.
c. The ADU is to be constructed within the existing or proposed primary dwelling or accessory structure.
d. The ADU is located in an area of the City where on-street parking permits are required but not offered to the occupant of the ADU.
e. The ADU is located within one block of a car share vehicle pick-up location, as established by the City.
f. When a permit application for an ADU is submitted with a permit application to create a new single-family dwelling or a new multifamily dwelling on the same lot; provided, that the ADU or the parcel satisfies any other criteria listed in this subsection (E)(4).
F. Fire sprinklers shall be required for an ADU or JADU if they are provided or required for the primary unit. The construction of an ADU or JADU shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling.
G. An ADU or JADU shall have independent exterior access.
H. Nonpermitted Structures.
1. Notwithstanding any other provision in this chapter, the City shall not require correction of nonconforming zoning code development regulations or building code violations for the approval of a new ADU or JADU, provided the structure(s) does not present a threat to public health and safety.
2. Moreover, the City shall not require correction of nonconforming zoning code development regulations or building code violations for the approval of an existing, unpermitted ADU or JADU, provided the unpermitted structure(s) does not present a threat to public health and safety. (Ord. 770 §§ 6 – 9, 2024; Ord. 744 § 2 (Exh. A), 2020).
17.37.060 Nonconforming ADUs.
ADUs and JADUs legally constructed prior to adoption of the provisions contained in this title shall be considered nonconforming and subject to the provisions of Chapter 17.44 CMC pertaining to nonconforming uses and structures. (Ord. 744 § 2 (Exh. A), 2020).