Philadelphia ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Philadelphia, Pennsylvania means pulling a building permit from the local authority that issues it. ArchPermit tracks 13 source-cited requirements (6 required, the rest conditional) for this jurisdiction. Submittals go through eCLIPSE online portal (L&I). These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in City of Philadelphia. Every item links to its authoritative source; items that vary are flagged to confirm locally.
A Philadelphia 'ADU' is a by-right zoning use under Title 14 § 14-604(11), but by code it must be carved out of the INTERIOR of the existing principal building or a PRE-EXISTING detached accessory building — a newly-built detached backyard ADU is NOT as-of-right and requires a Zoning Board of Adjustment variance. In most cases you must obtain a zoning permit before the building permit. The ADU zoning gates: owner-occupancy with a recorded affidavit + deed restriction, one ADU per lot, ADU floor area ≤800 sf (waived only for historic structures), lot ≥1,600 sf, principal structure semi-detached or detached. Confirm the exact permitted zoning districts with L&I (a 2022 checklist conflicts with current code).
- Building Permit Applicationrequired
Application stating the complete scope of work and current owner name/mailing address, filed in eCLIPSE under the legal OPA address.
source · reviewed 2026-06-22 - Construction Plans (sealed)required
To-scale plans (floor plans, elevations, foundation & wall-bracing details) with code summary, room uses, door/window schedules, ceiling heights, and wall/floor/roof types & ratings.
source · reviewed 2026-06-22 - Energy Conservation Documentation (REScheck + Air Barrier checklist)required
Residential energy-code compliance: a REScheck certificate plus an Air Barrier and Insulation checklist.
source · reviewed 2026-06-22 - Licensed Philadelphia Contractorrequired
A licensed Philadelphia contractor must be named for issuance, with active license, no tax delinquency, and current insurance (owner-occupied one/two-family exception for who performs the work).
source · reviewed 2026-06-22 - Owner-Occupancy Affidavit + Recorded Deed Restrictionrequiredverify locally
The ADU zoning gate under § 14-604(11): owner-occupancy with a recorded affidavit and deed restriction (confirm the current recorded-document form with L&I).
source · reviewed 2026-06-22 - Valid Zoning Permit (prerequisite)required
A pre-requisite approval that must be valid on the submission date — where ADU eligibility under § 14-604(11) is confirmed. In most cases obtained before the building permit.
source · reviewed 2026-06-22 - Flood Plain Information Form (FP-G)conditional
Required if the property is in a designated flood hazard area.
source · reviewed 2026-06-22 - Geotechnical Investigation Report (sealed PE)conditional
Required except for additions under 2,000 sf of built-upon area and three stories or less; covers sheeting/shoring and excavation monitoring.
source · reviewed 2026-06-22 - PA-Licensed Design Professional Sealconditional
Architect/engineer seal required if the cost of work exceeds $25,000 or any structural work is proposed.
source · reviewed 2026-06-22 - PWD Stormwater Plan Review (ERSA)conditional
Required when the project disturbs 5,000 sf or more of earth; PWD approval precedes the zoning/building permit.
source · reviewed 2026-06-22 - Proof of Ownership (settlement sheet or deed)conditional
If the property was recently sold, submit a copy of the settlement sheet or deed.
source · reviewed 2026-06-22 - Special Inspections Documentationconditional
When special inspections apply: a named licensed agency, design professional in responsible charge, sealed inspection schedule, and three-party agreement.
source · reviewed 2026-06-22 - Waste Hauler Formconditional
Required for new construction, addition, and alteration projects that require plans.
source · reviewed 2026-06-22