Mono County, CA Accessory Structures: Garage Conversions (2026)

Garage conversions are addressed directly in Mono County's General Plan Land Use Element Chapter 16. Section 16.040.A(i) allows an ADU or junior ADU located within a single-family dwelling, the existing space of a single-family dwelling, or an existing accessory structure (which includes a garage) to be permitted by building permit, with an expansion of no more than 150 square feet allowed only to accommodate ingress and egress. Critically, Section 16.050.G states that no setback shall be required for an existing garage that is converted to an accessory dwelling unit, and where an ADU is constructed above a garage, a setback of no more than four feet from the side and rear lot lines applies, provided the design demonstrates snow will not shed onto adjacent properties and fire-safety standards are met. The converted space must have exterior access and meet the California Building Code minimums for an efficiency dwelling unit (Section 16.020). No passageway is required (16.050.G). Fire sprinklers are required in the converted ADU only if they were required for the primary residence (16.050.F). Converting a garage that eliminates required parking does not, by itself, require replacement parking when a parking exemption under Section 16.050.D applies (for example, within one-half mile of public transit).