Erie, PA Accessory Structures: ADU Rules (2026)

The City of Erie's zoning code now defines an Accessory Dwelling Unit as a single dwelling unit with provisions for sleeping, cooking, and sanitation whose use is secondary to that of the principal dwelling or building on the same lot, distinguishing an interior ADU (existing space converted within the primary dwelling, such as an attic or basement), an attached ADU (added to the front, side or rear of the primary structure or built above an attached garage), and a detached ADU (structurally separate, including a unit built as a stand-alone structure or added to an existing detached garage). These definitions and the related permitted/conditional-use criteria were adopted through Ordinance No. 52-2024 (passed September 18, 2024), which amended Article 2 (District Regulations) and Article 3 (General Regulations) of the Erie Zoning Code. Because Erie's underlying detached-accessory-building standards in Zoning Ordinance Sec. 205.18 cap most detached accessory buildings in 'R' districts at 720 square feet and 15 feet in height, applicants should confirm the current ADU size and placement limits with the Zoning Office before designing a unit. Pennsylvania's Municipalities Planning Code (Act 247, 53 P.S. Sec. 10101 et seq.) is the enabling authority under which Erie regulates ADUs.