Chino Hills, CA Building Safety: Anti-Mansionization (2026)

Chino Hills does not cap floor area ratio for its residential zone districts (CHMC § 16.10.030 table item F: "No maximum floor-to-area ratio; FAR will be subject to meeting parking and landscaping standards"), so the city polices oversized additions and rebuilds through design review rather than a hard size cap. The trigger is set in § 16.10.050(A)(2)(a): any residential construction on vacant property, and any structural addition or reconstruction project equal to fifty percent or more of the floor area of the existing on-site buildings, must comply with the city's Residential Design Guidelines and the parking requirements of Chapter 16.34. Additions below the 50 percent threshold skip the parking requirement if the existing home already has two covered spaces, but the design guidelines still apply once a project crosses that line.

The design control aimed most directly at bulk sits in § 16.06.130(B): any new single-family dwelling or addition that creates or modifies a second-story element must be designed with appropriate treatments on every street-facing elevation, front, side, and rear, that provide visual relief and avoid an uninterrupted flat wall running from the ground floor to the second story. The Community Development Director or designee makes that call, and single-family detached development is subject to design review under § 16.10.050 before or alongside map approval, plan approval, or building permit issuance. In practice this means a homeowner adding a full second story cannot simply stack a box on the existing footprint; the elevation has to be broken up with articulation, so a project's mass gets shaped even where no numeric FAR limit applies.