Oakland County, MI Building Setbacks & Zoning: Lot Coverage Limits (2026)

Lot coverage is a critical zoning standard in Oakland County because the region's storm-drainage system depends on each lot retaining some pervious area for infiltration before runoff reaches the Clinton, Rouge, or Huron River watersheds that ultimately drain to the Great Lakes. Royal Oak, Madison Heights, Ferndale, and Hazel Park (older inner-ring suburbs on 40-50 ft wide lots) commonly cap principal and accessory building coverage at 30-35 percent of lot area. Bloomfield Township and Bloomfield Hills (larger lots, often 1+ acres) typically cap building coverage at 15-25 percent to preserve the rural-residential character. Most Oakland County codes separately limit accessory building footprint in the required rear yard to 25-30 percent of the rear yard area. Driveways, parking areas, patios, pool decks, and walkways are usually counted as impervious surface that contributes to a separate impervious-coverage cap — frequently 50-60 percent total. Communities increasingly require stormwater retention (rain gardens, dry wells, permeable pavers) when redevelopment exceeds the impervious threshold, in line with the Oakland County Drain Commissioner's MS4 stormwater permit. New construction or major additions exceeding the cap require either a redesign or a dimensional variance from the local Zoning Board of Appeals — practical difficulty must be shown under MCL 125.3604.