Chino Hills, CA Accessory Structures: ADU Rules (2026)

Chino Hills implements California's ADU law through Section 16.10.140 of its Development Code (Title 16). ADUs that meet the city's objective standards are approved ministerially, without a public hearing. Per the city's Accessory Dwelling Units page, a detached ADU may be up to 850 square feet for a one-bedroom unit or 1,000 square feet for a unit with two or more bedrooms. An attached ADU is held to the same square-footage figures but the total floor area of the ADU cannot exceed 50% of the main house's floor area. A junior accessory dwelling unit (JADU) is capped at 500 square feet and must be contained within the walls of the existing or proposed single-family residence. The maximum height for a one-story detached ADU is 18 feet. Side-yard (interior and side-street) and rear-yard setbacks are a minimum of 4 feet, and that 4-foot setback to the side and rear property lines is measured beginning at the eave/overhang of the roof. One off-street parking space (not on the street) is required for any ADU with one or more bedrooms, in addition to the parking required for the main house, unless the property qualifies for an exemption (within a half-mile walking distance of transit, part of the existing home or accessory structure, in an area where on-street parking permits are required, or near a car-share location). The city references CHMC 16.10.140(H) for districts where ADUs are ineligible and 16.10.140(I)(2) for multifamily/mixed-use requirements.