Pittsburgh, PA Accessory Structures: ADU Permits (2026)

Pittsburgh Code Title 9 (Zoning Code) regulates ADUs as accessory uses. Section 911.04.A.10 lists Accessory Dwelling Unit standards: ADUs are permitted in R1A-VH, R1A-H, R1A-M, R1D-VH, R1D-H, R1D-M, R2 and R3 residential districts subject to compliance with the section. Maximum ADU floor area is typically 600-800 sq ft or 40% of principal dwelling, whichever is less. The principal dwelling must contain at least one bedroom. ADUs require the same setbacks as the principal residential use of the district. Off-street parking requirements have been substantially relaxed under recent zoning reforms but specific district rules apply. Building permits, plumbing permits (Allegheny County licensed plumber), electrical permits (City of Pittsburgh registered electrical contractor), and mechanical permits are required and filed through PLI's OneStopPGH portal. Historic district properties (Mexican War Streets, Manchester, Allegheny West, Deutschtown, Roslyn Place, others) require Historic Review Commission (HRC) approval. Pennsylvania has no statewide ADU preemption law - municipal zoning controls.