Garden Grove, CA Accessory Structures: ADU Rules (2026)

020, ADUs are allowed by right on any lot in Garden Grove zoned to allow single-family or multiple-family residential use that already has, or is proposed to have, a legally developed dwelling; JADUs are confined to lots zoned single-family. 030 caps a single-family lot at one ADU plus one JADU. Multi-family lots get more room: up to eight detached ADUs on a lot with an existing multi-family building (never more than the number of existing units), up to two detached ADUs on a lot proposed for new multi-family development, and one or more converted ADUs built inside non-livable space, capped at 25% of the existing multi-family unit count.

040 sets minimum unit sizes of 150 square feet for an efficiency unit, 220 for a studio, 500 for one bedroom, and 700 for two or more bedrooms, and overrides floor-area-ratio, front-setback, building-separation, lot-coverage, open-space, or minimum-lot-size standards to the extent needed to allow construction of an ADU up to 800 square feet. 070, or within 30 days for a City pre-approved or previously approved detached ADU plan. Existing nonconforming zoning conditions, building code violations, or unpermitted structures that do not threaten health and safety are not grounds to deny the permit, and an ADU does not trigger a fire-sprinkler retrofit of the primary home if sprinklers were not already required there.