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, and 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
Philadelphia ADU permit questions
- Do I need a permit to build an ADU in Philadelphia?
- Yes. An accessory dwelling unit (ADU) in Philadelphia requires a building permit. ArchPermit tracks 13 cited requirements for this jurisdiction (6 required, the rest conditional). Always confirm the exact forms, fees, and code edition with the local permitting authority that issues the permit.
- What does an ADU permit package require in Philadelphia?
- Core required items include: Building Permit Application; Construction Plans (sealed); Energy Conservation Documentation (REScheck + Air Barrier checklist); Licensed Philadelphia Contractor; Owner-Occupancy Affidavit + Recorded Deed Restriction; Valid Zoning Permit (prerequisite). Each requirement links to its authoritative source, and nothing is permit-ready until an independent licensed professional reviews and seals it.
- How are ADU permits submitted in Philadelphia?
- Philadelphia accepts permit submittals via eCLIPSE online portal (L&I). ArchPermit prepares a draft package you can submit there after a licensed architect reviews and seals it.