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

Because Trinity County is entirely unincorporated, lot-coverage limits come from the County's zoning ordinance (Title 17), and the maximum coverage depends on the parcel's district. In the R-2 Duplex Residential district, the maximum allowable lot coverage by all structures is forty percent (Sec. 17.17.070), and the minimum lot area is three thousand square feet per family unit (Sec. 17.17.120). Other districts use different coverage percentages and minimum lot sizes - rural and agricultural districts generally have far lower coverage and much larger minimum parcels - so owners must look up their own zone. Lot coverage measures the share of the parcel occupied by buildings and structures; it works together with the district's required yards (setbacks) and height limit to control overall density and bulk. Larger rural parcels typically have generous remaining coverage capacity, while smaller residential lots can be constrained by the combination of setbacks and the coverage cap. Detached accessory structures count toward coverage, though very small ones (one-story, 120 square feet or less, general storage) are exempt from a building permit under Sec. 15.04.140. Because the coverage percentage and minimum lot area both vary by district, confirm the exact figures for your parcel with the Trinity County Planning Division before adding buildings.