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

Modoc County controls how much of a lot can be built upon mainly through minimum lot size, minimum lot width, and zone-specific maximum lot coverage. In the Residential-Low Density (RL) zone, §18.32.060(D) caps maximum lot coverage at 60 percent; the Residential-High Density (RH) zone, §18.36.060(D), uses the same 60 percent ceiling. For multi-family dwelling projects, §18.110.080(A)(2) limits maximum building and impervious-surface coverage to 70 percent of the site (excluding public rights-of-way) and requires at least 10 percent improved landscaped coverage. Rural and agricultural zones such as Rural Residential (RR), Agricultural General (AG), and Agricultural Exclusive (AE) rely on large minimum lot sizes rather than a stated coverage percentage — the RR zone, for example, ranges from 1 to 15 acres minimum lot size with no lot under 2 acres unless public sewer is available (§18.30.060), which inherently keeps building footprints small relative to parcel area. Lot size is measured as gross area held in fee, with road easements excluded when the minimum lot size is one acre or less (§18.110.020). Because coverage limits are stated only in certain zones, owners should verify their parcel's zone and any applicable coverage cap with the Planning Department before designing a large structure or addition.