Tustin, CA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Lot coverage - the share of a lot that may be occupied by buildings - is governed by zoning district in Chapter 2 (Zoning) of the Tustin City Code. In the R1 Single-Family Residential district and the E4 Residential Estate district, the maximum lot coverage is generally about 40 percent. Denser residential districts allow more coverage: the R2 Duplex district is generally around 50 percent and the R3 Multiple-Family Residential district around 65 percent. These districts also pair coverage caps with required usable open space - for example, R1 and E4 require a minimum of roughly 1,000 square feet of clear, unobstructed usable open space on the rear third of the lot, which limits how much of the rear yard can be built upon even within the coverage allowance. Minimum lot areas and widths accompany these standards (for instance, R1 typically requires about a 7,200-square-foot lot and 60-foot width, and E4 about 10,000 square feet and 80-foot width). Special overlays and Planned Community districts may set their own coverage standards, and accessory structures and ADUs are subject to additional state and local provisions. Because the exact percentage depends on the parcel's district, owners planning additions or new structures should confirm coverage, open-space and setback figures through a zoning verification or with the Community Development Department before finalizing plans. Fences and walls do not count toward building lot coverage but are subject to separate height, setback and permit rules.