San Clemente, CA Accessory Structures: Garage Conversions (2026)

San Clemente regulates garage conversions through its accessory dwelling unit section, Municipal Code § 17.28.270, which carries out California Government Code Sections 66310-66342. Under subsection C, an accessory dwelling unit (ADU) or junior accessory dwelling unit (JADU) is approved in any residential or mixed-use zoning district, and in commercial districts where housing is authorized, on issuance of a building permit, as long as there is an existing or proposed dwelling on the lot.\n\nThe setback rule is the main benefit for a garage owner. Subsection E.2.a says a conversion of existing enclosed floor area, garage, or carport needs no additional setback beyond the existing provided setback.

Subsection E.2.b gives the same relief to a teardown and rebuild, but only when the new unit stays within the same footprint and does not exceed the existing structure's size or height. When the new ADU replaces a detached garage, the building permit and the demolition permit are reviewed and issued concurrently.\n\nSubsection D decides how many units a garage can become. For a single-family lot, an ADU or JADU can occupy the existing space of the house or of an attached accessory structure, and the footprint can grow by no more than 150 square feet beyond the same physical dimensions of the existing attached structure, with that growth limited to ingress and egress (D.1.a).

One detached accessory structure, such as a detached garage, can be converted to an ADU (D.3). On a multi-family lot, garages are listed among the non-livable spaces that can be converted, up to 25 percent of the existing units and never fewer than one (D.5).\n\nSize and parking follow the same pattern. The 850 and 1,000 square foot ceilings in E.4.a do not apply to an ADU converted from existing space of a single-family dwelling or existing accessory structure (E.4.b), while a JADU is capped at 500 square feet (E.4.d).

One parking space is required per ADU (E.9.a), but none for a unit converted from an existing accessory structure (E.9.c.ii). Outside the coastal zone, the off-street spaces a garage or carport provided do not have to be replaced (E.9.c.viii), and any parking that is required can be tandem or on an existing driveway (E.9.b).\n\nFire sprinklers are not required for the ADU unless the principal dwelling needs them (E.6), and no passageway is required (E.8). Under subsection F, an ADU under 750 square feet pays no impact or connection fee, while a larger one pays in proportion to the primary dwelling's floor area. Ordinance 1810, adopted June 16, 2026, is the latest amendment to the section.