Doylestown, PA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Lot coverage and impervious surface regulation in Bucks County happens at the municipal level under the PA Municipalities Planning Code (53 P.S. §10603) with state oversight through the PA Stormwater Management Act (32 P.S. §680.1 et seq., Act 167 of 1978). Two related measurements are commonly regulated: (1) Building coverage — percentage of lot covered by primary and accessory structures (typically 15-25% in R-1, 20-35% in R-2/R-3, up to 50% in commercial); (2) Impervious surface coverage — percentage of lot covered by buildings PLUS driveways, walkways, patios, pools, and other non-porous surfaces (typically 30-45% in R-1, 40-55% in R-2, up to 80% in commercial zones). Permeable pavers, pervious concrete, and gravel may receive 50% credit (reducing calculated coverage) in many Bucks municipalities with stormwater-progressive codes. Bucks County has adopted Act 167 stormwater management plans for major watersheds (Neshaminy Creek, Tohickon Creek, Pennypack Creek, and others), which impose minimum standards on municipalities. Projects creating more than 1,000-5,000 square feet of new impervious surface (threshold varies) typically trigger stormwater management plan review, with projects over 1 acre of disturbance requiring PA DEP NPDES permits under the Clean Streams Law (35 P.S. §691.1). Bucks County Conservation District reviews erosion and sediment control plans. Exceeding lot coverage requires a zoning variance from the Zoning Hearing Board with hardship demonstration.