Arapahoe County, CO Building Setbacks & Zoning: Lot Coverage Limits (2026)

Arapahoe County Land Development Code §3-2 caps lot coverage by building and impervious surfaces depending on zoning district. R-1 (Suburban Residential) typically 35% building footprint / 50% total impervious. R-2 allows 40% building / 55% impervious. R-A (Residential Agricultural, 2.5+ acre) limits to 20% building coverage. Aurora UDO §146-4 uses 40% lot coverage in R-1 zones. Centennial Municipal Code §12-2 follows 40% coverage. Coverage calculations include the primary structure, attached and detached garages, sheds, gazebos, covered patios, driveways, and sidewalks. Colorado's semi-arid climate creates heightened stormwater concerns; properties in the Cherry Creek Watershed Protection Zone face additional impervious surface limits under the Cherry Creek Reservoir Control Regulation (5 CCR 1002-72) protecting water quality for the reservoir which supplies metro drinking water. Permeable pavers, gravel driveways, and turf block may receive 50% credit toward coverage calculations in most Arapahoe County jurisdictions. Exceeding coverage requires a variance from the Board of Adjustment. Stormwater management plans triggered for development exceeding 50% impervious surface per Urban Drainage and Flood Control District standards.