San Anselmo Municipal Code Art. 3 Accessory Dwelling Unit and Junior Accessory Dwelling Unit Development…

Unless exempt from an ADU permit pursuant to Section 10-6.103(c) of this chapter, an ADU must comply with the following objective development standards to receive an ADU permit.

(a) Zoning Conformance. An ADU shall meet the development standards of the zoning district in which it is located except as modified by this section.

(b) Height. Unless otherwise provided for in this chapter, an attached or detached ADU must comply with the following height requirements.

(1) A maximum height of sixteen (16) feet for a detached ADU on a lot with an existing or proposed single family or multifamily dwelling unit.

(2) A maximum height of eighteen (18) feet for a detached ADU 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 Public Resources Code section 21155 of the Public Resources Code, as may be amended from time to time. The Town shall also allow an additional two (2) feet in height to accommodate a roof pitch on the ADU that is aligned with the roof pitch of the primary dwelling unit.

(3) A maximum height of eighteen (18) feet for a detached ADU on a lot with an existing or proposed multifamily, multistory dwelling.

(4) A maximum height of twenty-five (25) feet or the height limitation in the local zoning ordinance that applies to the primary dwelling, whichever is lower, for an ADU that is attached to a primary dwelling. An ADU under this section may not exceed two (2) stories.

(c) Lot Size. There shall be no minimum lot size required for an ADU.

(d) Lot Coverage and Floor Area Ratio. The ADU shall comply with the lot coverage and floor area ratio requirements of the underlying zoning district unless otherwise required by this chapter.

(e) Setbacks.

(1) No setbacks shall be required for the following:

(A) An existing living area that is converted to an ADU or a portion thereof;

(B) An existing accessory structure that is converted to an ADU or a portion thereof; or

(C) A structure constructed in the same location and to the same dimensions as an existing structure that is converted to an ADU or to a portion thereof.

(2) A setback of no more than four (4) feet from the side and rear lot lines shall be required for an ADU that is not converted from an existing structure or a new structure constructed in the same location and to the same dimensions as an existing structure.

(f) Size. ADUs shall be subject to all of the following requirements related to size.

(1) Except as provided in subsection (2) below, ADUs shall be limited to the following maximum sizes:

(2) ADUs may exceed the maximum unit sizes provided in subsection (1) above following approval through the discretionary design review process as set forth in the San Anselmo Municipal Code Title 10, Chapter 3, Article 15 Design Review. In no case shall an ADU exceed one thousand two hundred (1,200) square feet of gross floor area.

(3) The gross floor area of attached or interior ADUs shall not exceed fifty (50%) percent of the existing living area (as defined in California Government Code Section 66313, as amended from time to time) of the primary residence. Notwithstanding the prior sentence, an attached or interior ADU may contain at least the maximum size set forth in Section 10-6.301(f)(1).

(g) Separate Entry, Kitchen and Bathroom. All ADUs shall contain a separate entrance, kitchen, and bathroom independent of the primary residence.

(h) Exception. The Town shall not impose any requirement for a zoning clearance or separate zoning review or any other minimum or maximum size for an ADU, size based upon a percentage of the proposed or existing primary dwelling, or limits on lot coverage, floor area ratio, open space, front setbacks, and minimum lot size, for either attached or detached dwellings that does not permit at least an eight hundred (800) square ADU with four-foot side and rear yard setbacks to be constructed in compliance with all other local development standards.

(Ord. No. 1172, § 3, 12-13-2022; Ord. No. 2025-1188, § 2(Exh. A), 3-11-2025)

Unless exempt from an ADU permit pursuant to Section 10-6.103(c) of this chapter, all ADUs must comply with the following objective standards to receive an ADU permit. Where an application does not meet the objective design standards set forth herein, the application may undergo the standard discretionary design review process as set forth in the San Anselmo Municipal Code Title 10, Chapter 3, Article 15 Design Review.

(a) Building Design. The materials and colors of the ADU's exterior walls, roof, windows, and doors shall be of a complimentary material, color, and style the primary dwelling, including roof, eaves, windows, accents, and doors.

(b) Landscape Design. Landscaping shall be provided around the ADU, and its location shall ensure defensible space. Fire-resistant and low-water-use plants shall be included in the landscape design. Landscaping shall be included to screen mechanical and structural elements of the ADU, including, but not limited to, foundations, retaining walls, condensers, and transformers.

(c) Entrance. The entrance to the ADU shall face towards the interior of the lot and/or away from neighboring development, unless the ADU is directly accessible from an alley, public path, or public street.

(d) Windows and Doors. Windows in an ADU that is located less than ten (10) feet from a rear or side property line shall be clerestory windows or use frosted or obscure glass. Any new door that faces an adjoining residential property located less than ten (10) feet from a rear or side property line shall either not include windows, or all windows must be made of opaque glass.

(e) Exterior Lighting. All exterior lighting shall be low wattage, shielded, and directed downward.

(f) Skylights. Where visible from off-site locations, skylights shall not have white or light opaque colored exterior lenses.

(g) Historical. An ADU that includes exterior alterations or additions to a property that is listed in the California Register of Historic Places or on a local historical register shall not be approved if it may cause an adverse impact to the historical significance of the property. There shall be no design exception to this requirement.

(h) Heritage Trees. No heritage tree (as defined in Title 4, Chapter 13 of the San Anselmo Municipal Code) shall be removed in conjunction with the construction of an ADU until a building permit has been issued for the ADU.

(Ord. No. 1172, § 3, 12-13-2022; Ord. No. 2025-1188, § 2(Exh. A), 3-11-2025)

(a) One (1) parking space is required per ADU unless otherwise provided for in this chapter.

(b) Parking may be provided through tandem parking on an existing driveway.

(c) Off-street parking to satisfy parking requirements shall be permitted in setback areas in locations determined by the Town unless specific findings are made that parking in setback areas is not feasible based on specific site, regional, topographical, or fire and life safety conditions, which conditions shall include but are not limited to circumstances where parking would impede reasonable emergency and fire access.

(d) When a garage, carport, covered parking structure, or uncovered parking space is demolished in conjunction with the construction of an ADU or converted to an ADU, it is not required that those off-street parking spaces be replaced.

(e) Parking Exemptions. An ADU shall be exempt from the parking requirement of this section if the unit is:

(1) Located within one-half mile walking distance of a public transit stop.

(2) Located within an historic district, as may be designated by the Town Council from time to time;

(3) The ADU is part of the proposed or existing primary residence or an accessory structure;

(4) When on-street parking permits are required but not offered to the occupant of the ADU;

(5) When there is a designated car share vehicle pick up or drop off location (as defined by the California Vehicle Code) located within one (1) block of the ADU;

(6) 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 paragraph; or

(7) The unit is an attached or detached ADU that is up to eight hundred (800) square feet of floor area, with minimum four (4) foot side and rear yard setbacks, in compliance with the height limitations as provided in section 10-6.301(b) of this chapter, on a lot with a proposed or existing single-family dwelling.

(Ord. No. 1172, § 3, 12-13-2022; Ord. No. 2025-1188, § 2(Exh. A), 3-11-2025)

Unless otherwise provided for in this chapter, JADUs are subject to the following objective standards:

(a) Location and Number. A JADU shall be located within an existing or proposed single-family residence. For purposes of this paragraph, enclosed uses within the residence, such as attached garages, are considered a part of the proposed or existing single-family residence. A JADU is not permitted in a detached accessory structure. One (1) JADU is allowed per lot. If there are multiple detached single-family residential units on One (1) lot, only One (1) JADU is allowed.

(b) Unit Size. No JADU unit shall be less than one hundred fifty (150) feet or more than five hundred (500) square feet in size. The square footage of any shared sanitation facilities with the primary dwelling unit shall not be included in the square footage calculation.

(c) Access. The JADU unit shall have a separate exterior entrance from the primary dwelling unit.

(d) Interior Connection and Bathroom Facilities. A JADU unit may include separate bathroom facilities, or it may share such facilities with the primary dwelling unit. If a permitted JADU does not include a separate bathroom, the JADU unit shall include a separate entrance from the main entrance to the structure, with an interior entry to the main living area. Unless sharing bathroom facilities with the primary dwelling unit, a JADU is not required to have an interior connection to the primary dwelling.

(e) Kitchen Facilities. The JADU shall include an efficiency kitchen, which shall include a cooking facility with appliances, and a food preparation counter and storage cabinets that are of reasonable size in relation to the size of the JADU.

(f) Parking. No parking is required for a JADU.

(g) Entryways. A JADU must include a separate entrance from the main entrance to the proposed or existing single-family residence.

(Ord. No. 1172, § 3, 12-13-2022; Ord. No. 2025-1188, § 2(Exh. A), 3-11-2025)

If an ADU application does not otherwise meet the requirements in this chapter, an applicant may request exceptions to this chapter and receive ADU approval by applying for a conditional use permit (CUP). Any exceptions approved pursuant to this section must also comply with all objective design review standards as set forth in Section 10-6.302, if applicable, and shall be reviewed through the standard CUP process. Any detached ADU approved herein shall not exceed one thousand two hundred (1,200) square feet.

(Ord. No. 1172, § 3, 12-13-2022; Ord. No. 2025-1188, § 2(Exh. A), 3-11-2025)