San Anselmo Municipal Code Art. 1 Accessory Dwelling Units and Junior Accessory Dwelling Units Purpose,…

The purpose of this chapter is to provide for the creation and regulation of accessory dwelling units (ADUs) and junior accessory units (JADUs) in a manner consistent with State law.

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

For the purposes of this chapter the following definitions apply:

"Accessory dwelling unit" or "ADU" means an attached or a detached residential dwelling unit that provides complete independent living facilities for one (1) or more persons and is located on the same lot as the proposed or existing primary residence. It shall include permanent provisions for living, sleeping, eating, cooking, and sanitation. An accessory dwelling unit also includes an efficiency unit, as defined in Section 17958.1 of the Health and Safety Code, and a manufactured home, as defined in Section 18007 of the Health and Safety Code.

"Accessory structure" means a structure that is accessory and incidental to a dwelling located on the same lot.

"Attached Accessory Dwelling Unit" or "Attached ADU" means an ADU that shares a common wall with the primary dwelling unit on the lot either by being constructed as a physical expansion (addition) to the primary dwelling unit, conversion of an existing attached garage to the primary dwelling unit, or construction of a basement underneath an existing primary dwelling unit.

"Detached Accessory Dwelling Unit" or "Detached ADU" means an ADU that is constructed as a separate structure from the primary dwelling unit on the lot of by the conversion (full or partial) of an existing detached accessory structure into an ADU.

"Efficiency kitchen" shall have the same meaning as defined in State law and means a cooking facility with appliances and a food preparation counter and storage cabinets that are of reasonable size in relation to the unit.

"Efficiency unit" shall have the same meaning as defined in California Health and Safety Code section 17958.1, as amended from time to time and means a unit with a minimum floor area of one hundred fifty (150) square feet.

"Junior Accessory Dwelling Unit" or "JADU" shall have the same meaning as defined in State law and means a unit located entirely within an existing or proposed single-family residence that is no more than five hundred (500) square feet, includes an efficiency kitchen, and includes either its own separate sanitation facilities or shares sanitation facilities with the existing or proposed single-family residence.

"Livable space" means a space in a dwelling intended for human habitation, including living, sleeping, eating, cooking, or sanitation.

"Living area" shall have the same meaning as defined in State law and means the interior habitable area of a dwelling unit including basements and attics, but does not include a garage or an accessory structure.

"Multifamily dwelling" means a structure with two (2) or more attached dwellings on a single lot.

"Nonconforming zoning condition" shall have the same meaning as defined in State law and means a physical improvement on a property that does not conform with current zoning standards.

"Objective standards" shall have the same meaning as defined in State law and means standards that involve no personal or subjective judgment by a public official and are uniformly verifiable by reference to an external and uniform benchmark or criterion available and knowable by both the development applicant or proponent and the public official prior to submittal.

"Passageway" shall have the same meaning as defined in State law and means a pathway that is unobstructed clear to the sky and extends from a street to one (1) entrance of the ADU.

"Proposed dwelling" shall have the same meaning as defined in State law and includes a dwelling that is the subject of a permit application that meets the requirements for permitting.

"Public transit" shall have the same meaning as defined in State law and means a location, including, but not limited to, a bus stop or train station, where the public may access buses, trains, subways, and/or other forms of transportation that charge set fares, run on fixed routes, and are available to the public.

"Tandem parking" shall have the same meaning as defined in State law and means two (2) or more automobiles are parked on a driveway or in any other location on a lot, lined up behind one (1) another.

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

(a) ADU Permit. Unless exempt from an ADU Permit pursuant to Section 10-6.103(c) of this chapter, an ADU must receive an ADU permit in compliance with the standards and requirements set forth in this chapter.

(b) ADUs are permitted on single- and multifamily zoned lots, and JADUs are permitted in single-family zoned lots.

(c) Exemptions from ADU Permit. The Town shall ministerially approve a building permit application for an ADU and/or JADU, and no ADU permit shall be required to create any of the following. Projects exempt from an ADU permit under this section shall remain subject to other applicable construction-related permit requirements including but not limited to building and grading permits, and all applicable fire code requirements.

(1) Interior on Single-Family Lot. One ADU and/or one JADU if the unit(s) is:

a. Within the proposed or existing space of a single-family dwelling or an existing accessory structure, plus an additional one hundred (150) square feet if required to accommodate ingress and egress;

b. Has exterior access from the proposed or existing single-family dwelling; and

c. Has side and rear yard setbacks sufficient for fire safety as determined by the Ross Valley Fire Department.

d. If a JADU, the unit complies with the requirements of California State law.

(2) Detached on Single-Family Lot. One (1) newly constructed 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. The ADU may be combined with a JADU located on the same lot.

(3) ADUs on Interior of Multifamily Dwelling. Multiple ADUs within the portions of existing multifamily dwelling structures that are not used as livable space, including but not limited to, storage rooms, boiler rooms, passageways, attics, basements, or garages, if each unit complies with State building standards for dwellings. At least one (1) ADU within an existing or proposed multifamily dwelling and up to twenty-five (25%) percent of the number of existing permitted multifamily dwelling units rounded down to the nearest whole number shall be allowed.

(4) Detached ADUs on Multifamily Lot.

a. (ii)

Multiple ADUs, not to exceed the number specified in clause (ii) or (iii) herein as applicable, located on a lot that has an existing or proposed multifamily dwelling, but are detached from that multifamily dwelling in compliance with the height limitations as provided in Section 10-6.301(b) of this chapter, and side and rear yard setbacks of no more than four (4) feet.

(ii) On a lot with an existing multifamily dwelling, not more than eight (8) detached ADUs. However, the number of ADUs allowable pursuant to this clause shall not exceed the number of existing units on the lot.

(iii) On a lot with a proposed multifamily dwelling, not more than two (2) detached ADUs.

b. If the existing multifamily dwelling has a rear or side yard setback of less than four (4) feet, no modification to the existing multifamily dwelling shall be required as a condition of approving the ADU application if the ADU satisfies the requirements of this subparagraph.

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