From Marin County Code, Chapter 22.32.120 – Residential Accessory Dwelling Units
Applicability. The provisions of this Section shall apply to residential accessory dwelling units and junior accessory dwelling units.
- Within a single family residential zone, an application for a building permit to create one accessory dwelling unit per single-family residential lot is exempt from the standards of this section if the following applies: (1) the unit is entirely contained within a legal single-family residence that was in existence as of January 1, 2017 or a legal residential accessory structure that was in existence as of January 1, 2017; (2) the unit has independent exterior access from the existing residence, and; (3) the side and rear setbacks are sufficient for fire safety.
- A junior accessory dwelling unit is exempt. A property owner may voluntarily have a living space recognized as a junior accessory dwelling unit if it meets all of the following eligibility criteria:
- The unit shall be no more than 500 square feet in size and contained entirely within a single-family structure.
- The unit shall have a wetbar but shall not have a kitchen.
- The unit shall have a separate entrance from the main entrance to the building, with an interior entry to the main living area. The unit may include a second interior doorway for sound attenuation.
- The unit shall be the only junior accessory dwelling unit on the property.
- The property shall be owner occupied, except that owner occupancy is not required ifthe owner is a government agency, land trust, or housing organization.
- The property owner has recorded a deed restriction, which shall run with the land, that stipulates the following:
- A prohibition on the sale of the unit separate from the sale of the single-family residence, including a statement that the deed restriction may be enforced against future purchasers.
- A restriction on the size and attributes of the unit that conforms to this section.A copy of the recorded deed restriction must be provided to the agency.
D. Design Characteristics. A residential accessory dwelling unit shall be designed and constructed in conformance with the criteria listed below:
1. An accessory dwelling unit shall be built as a permanent residence with a kitchen as well as both a separate bathroom and separate entrance intended for the use of the occupants. The maximum floor area of an accessory dwelling unit shall not exceed 1,200 square feet.
No passageway shall be required in conjunction with the construction of an accessory dwelling unit.
Requirements for utility hookups and fire sprinklers shall comply with California Government Code Section 65852.2.
- Parking criteria. The lot on which the accessory dwelling unit is located shall have a minimum of one off-street parking space assigned to a studio or one-bedroom second unit or two off-street parking spaces assigned to a two-or-more-bedroom accessory dwelling unit. Off-street parking spaces assigned to the accessory dwelling unit shall be in addition to those required for the primary residence.The parking requirements indicated above shall not be imposed in any of the following instances:
- The accessory dwelling unit is located within one half mile of a public transit stop.
- The accessory dwelling unit is located within an architecturally and historically significanthistoric district.
- On-street parking permits are required but not offered to the occupant of the accessory dwelling unit.
- There is a car-share vehicle pick-up and drop-off site located within one block of the accessory dwelling unit.
- The accessory dwelling unit is no more than 500 square feet in floor area and contained entirely within the same building as the primary residence.
- A parking exception has been approved by the Department of Public Works.
- Setbacks. No setbacks shall be required to convert a legal garage into an accessory dwelling unit. In addition, setbacks of no more than five feet in the rear and side yards shall be required for an accessory dwelling unit that is constructed above a garage.
- Building and Septic Code. The accessory dwelling unit shall meet all applicable building and septic codes adopted by the County.
- Density. The accessory dwelling unit shall be the only additional accessory dwelling unit on the lot. However, a property owner may have both one accessory dwelling unit and one junior accessory dwelling unit on a single lot. Accessory dwelling units and junior accessory dwelling units are accessory uses and do not count towards the allowable density for the lot upon which the accessory dwelling unit is located.
- Limitation on sale. An accessory dwelling unit may be rented but shall not be sold separately from the single-family unit.
Accessory Dwelling Unit Permitting Procedure. Applications for Accessory Dwelling Unit Permits shall be approved ministerially without discretionary review or public hearing, pursuant to the Accessory Dwelling Unit Permit requirements established in Chapter 22.56 (Accessory Dwelling Unit Permits).