Describe the work, not just "fixing the deck"
Swapping worn walking boards, replacing stairs or railings, repairing joists, beams or posts, and making the deck bigger are different projects, and a permit office may treat them differently. None of the official pages below says that a same-size repair is automatically exempt, so don't assume it. If you're weighing a boards-only job, our guide to replacing deck boards without rebuilding the frame covers what has to be checked underneath first.
Philadelphia: an EZ permit is still a permit
L&I's page on permits without plans (EZ permits) lists residential decks up to 216 square feet, not including roof decks, among the projects that may qualify. An EZ permit doesn't require submitted plans, but the work has to comply with the matching EZ Standard, and the City says the permit will be revoked if the standard isn't followed. The application has to include the complete scope of work, and applications go through eCLIPSE, the City's online permit system. So the 216-square-foot figure tells you which permit route may be available; it doesn't mean a deck that size needs no permit.
Zoning is a separate question. Philadelphia's zoning permit page says alterations that don't change a structure's area, height, floor area or legal use don't need a zoning permit, and it lists decks no more than 12 inches above the ground and not over a basement or another story as exempt from zoning permits. Neither point answers whether a building permit is needed, so ask L&I about both.
Bucks County: each municipality runs its own permits
Pennsylvania's Department of Labor & Industry publishes a municipal list of Uniform Construction Code status and contacts, which shows whether each municipality enforces the state building code itself and gives a Building Code Official contact. The state notes that some municipalities don't keep their contact entry up to date, so confirm with the municipality directly.
Two local examples show why you need your own town's answer. Bristol Township's Permits & Licenses page lists residential decks among the work it permits, invites you to call the office if you're unsure, and accepts applications through an online Self-Service Portal or in person. Bensalem's Building and Planning forms page posts residential building permit forms, inspection requirements and a sample plot plan with setbacks. Neither one tells you the rule in a different township. If your address says Bristol, our guide to finding the right Bristol permit office explains why the borough and township are separate.
What to tell the permit office
Give a short written description: the deck's current size and height, whether it's attached to the house, exactly which parts will be replaced, and whether the footprint, stairs, location or supports will change. Ask what photos, drawings or site information they want, and which inspections are required. Bristol Township, for example, describes a rough inspection while work is still visible and a final inspection once it's complete, so ask before anything gets covered up.
If framing, posts or the connection to the house look damaged, have a qualified professional evaluate the structure; don't pull boards or framing apart yourself just to answer a permit question. Our guide to when deck joists or posts need a professional inspection lists the warning signs. If a contractor is doing the work, put who pulls the permit and schedules inspections in the written scope.
Get the answer in writing and keep it
For Philadelphia, L&I's code violation help page directs questions to its online help form with "Code or Permit Processing Questions" as the inquiry type, or 311, and points to its Permit Navigator for figuring out which approvals a project needs. In Bucks County, use the state list and your municipality's own permit page to reach the right office. Ask for a written answer tied to your described scope, and keep it with the permit and final inspection records. Philadelphia owners can also check what's already on file for the address; see our guide to looking up a home's permit history.