Accessory Structures in Philadelphia, PA (2026)
4 verified accessory structures rules for Philadelphia, Pennsylvania, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Philadelphia permits accessory dwelling units (ADUs) only on lots in the RSA-5 or CMX-1 base zoning districts (and certain overlay districts), under Zoning Code Section 14-604(11). The ADU must be inside the principal building or inside a detached accessory building (such as a detached garage) that already existed as of the Code's effective date, be no larger than 800 square feet, be limited to one per lot, and the owner must occupy either the principal or accessory unit.
ADUs allowed by-right in RSA-5 and CMX-1 only
Heavy RestrictionsPhiladelphia L&I Accessory Dwelling Unit Checklist (PZ_004_INF, Rev 3.2022), Step 3 - Additional Code Requirements; implementing Phila. Zoning Code Sec. 14-604(11)
Location: ADUs must be located within the principal building or within a detached accessory building, such as detached garages, that are in existence as of the effective date of this Zoning Code. Maximum of One ADU: No more than one accessory dwelling unit is allowed per lot. Floor Area of ADU: The floor area of the ADU may not exceed 800 square feet, OR the ADU is within a historic structure a...
ADU Owner Occupancy
An accessory dwelling unit or the main house must stay owner-occupied, locked in by a recorded deed restriction before final occupancy.
Philadelphia ADU Owner-Occupancy Deed Rule
Some RestrictionsPhiladelphia Code § 14-604(11)(e)
The principal dwelling unit or the accessory dwelling unit must be occupied by the owner of the subject lot. Before final occupancy of the accessory dwelling unit, the property owner shall record an affidavit and deed restriction, stating that the property owner will reside on the property, in either the principal or accessory dwelling unit. Once recorded, the deed restriction (requiring owner ...
Shed & Carport Rules
Philadelphia exempts a small shed from permits only when it is 120 sq. ft. or less, no taller than 15 ft. (one story), located in the rear yard, and accessory to a one- or two-family dwelling - per L&I Permit Guide PG_011 and the Zoning Code. A shed in a front or side yard, or larger than 120 sq. ft., requires a zoning permit, and a shed over 200 sq. ft. requires both a zoning and a building permit.
Sheds 120 sq ft or less in rear yard need no permit
Some RestrictionsPhiladelphia L&I Permit Guide PG_011 (FAQ: Shed), Permitting Requirements Table and Notes 1-5 (Sept. 2020)
The following table outlines permitting requirements for sheds that are accessory to one- or two-family dwellings: [Shed 120 ft2] In rear yard: Zoning Permit Not Required; In front / side yard: Zoning Permit Required; [> 120 ft2 and 130 ft2] Allowable per Zoning Code, Zoning Permit Required, Building Permit Not Required; [> 130 ft2 and 200 ft2] Not permitted per Zoning Code; [> 200 ft2] Zoning ...
Garage Conversions
Philadelphia does not have a standalone garage-conversion ordinance, but a detached garage is the prime candidate for an accessory dwelling unit under Zoning Code Section 14-604(11): an ADU may be located inside a detached accessory building such as a detached garage that already existed as of the Code's effective date, in the RSA-5 or CMX-1 districts, up to 800 sq. ft., owner-occupied. Converting a garage to any new use is a change of use requiring a use registration permit.
Detached garages can convert to ADUs by-right only
Some RestrictionsPhiladelphia L&I Accessory Uses FAQ (PZ_022_FAQ, June 2023), quoting Admin. Code A-301.1.5 and Zoning Code Sec. 14-604(1)(a)
Per A-301.1.5 a use registration permit is required for every new use commenced on any land or in any structure except for use as a single-family dwelling. Certain types of uses are considered accessory and are permitted in conjunction with the principle use without obtaining a separate permit. Per 14-604(1)(a), unless otherwise expressly stated in this Zoning Code, accessory uses and structure...