Plumbing Permit Requirements Checklist — What You Need Before Work Starts

Any work that changes the routing, size, or configuration of drain, waste, or vent (DWV) piping requires a permit in virtually all jurisdictions. This includes adding a new bathroom, relocating a toilet, extending a vent stack, or replacing a section of cast iron drain with PVC. Like-for-like repair of a small section (a cracked fitting or joint) is typically exempt, but replacing an entire drain run is not. When in doubt, call your local building department — a 5-minute phone call prevents a $5,000 problem.

Adding a new toilet, sink, shower, bathtub, dishwasher, or washing machine connection requires a permit because each new fixture requires proper drain sizing, venting, and trap placement per code. Relocating a fixture (moving a kitchen sink to an island, for example) also requires a permit because it changes pipe routing. Replacing a fixture in the same location (new toilet on the same flange, new faucet on existing supply lines) is typically exempt.

Water heater replacement rules vary significantly by jurisdiction. Many cities require a permit for any water heater replacement — even a like-for-like swap — because it involves gas connections, venting, seismic strapping, expansion tanks, and T&P valve discharge routing that must meet current code. Other jurisdictions exempt like-for-like replacements. Converting from tank to tankless always requires a permit due to gas line resizing, new venting, and electrical requirements. Check your city's specific requirement before scheduling the work.

Generally exempt from permits: replacing faucets, replacing shut-off valves, replacing a toilet on an existing flange, snaking or clearing drain clogs, replacing supply hoses, fixing leaks at joints, replacing garbage disposals, and minor repairs that don't change pipe routing or sizing. This exemption applies to residential work in most US jurisdictions — commercial work often has stricter requirements. Even for exempt work, all repairs must still comply with current plumbing code.

Most jurisdictions require a plumbing plan (also called a plumbing riser diagram) showing: existing pipe locations, proposed new pipe locations, pipe sizes, fixture locations, vent connections, and cleanout locations. This doesn't need to be a professional blueprint — a clear hand-drawn diagram on graph paper with accurate measurements is accepted in most residential applications. Show the main sewer connection, water service entry, water heater, and all fixtures with their drain and supply connections. Include pipe sizes (3-inch main drain, 2-inch branch, 1.5-inch vent, etc.).

The application requires: property address, assessor's parcel number (APN) or lot/block number, property owner's legal name, and — if using a contractor — their license number, bond number, and insurance certificate. Homeowners pulling their own permit (allowed for owner-occupied residences in most states) need to sign an owner-builder declaration acknowledging they'll do the work themselves and it meets code. Have your property deed or tax bill handy for the parcel number.

Plumbing permit fees vary by jurisdiction but typically run $50–$500 for residential work. Common fee structures: flat fee per fixture ($15–$75 per fixture added), percentage of project value (1–3%), or flat fee by project type. Water heater permits are often the cheapest ($50–$100). Full bathroom additions are the most expensive ($200–$500). Some jurisdictions charge a separate plan review fee ($50–$150) in addition to the permit fee. Most now accept online applications and credit card payment.

If hiring a contractor, verify their plumbing license is current and valid for your jurisdiction. A general contractor's license does not cover plumbing work in most states — a separate plumbing license (journeyman or master) is required. Ask for the license number and verify it online through your state's contractor licensing board. An unlicensed contractor pulling a permit (or worse, working without one) exposes you to liability, void warranties, and insurance claim denials. Licensed plumbers typically pull the permit themselves as part of the job.

The rough-in inspection happens after pipes are installed but before drywall closes the walls. The inspector verifies: correct pipe sizing, proper slope on drain lines (1/4 inch per foot minimum), adequate venting, proper support and hanging, correct materials, and compliant connections. Never close walls before this inspection — if you do and something fails, you'll tear out drywall to expose the work, fix it, and pay for re-inspection. Schedule 3–5 business days in advance; same-day inspections are rarely available.

Before the inspector arrives: remove any insulation covering new pipe work, ensure adequate lighting in the work area, clear access paths to all inspection points, and leave walls open so all connections are visible. The inspector cannot approve work they cannot see. If pipes are partially concealed, they'll either fail the inspection or require you to expose the work before they return. Label pipe sizes on the pipes themselves with a marker if they're hard to identify visually.

Keep a copy of your approved permit application and plumbing plans at the job site. The inspector compares installed work against the approved plans. If your installation differs from the plans (you moved a fixture, changed a pipe route, or modified the layout), you need a plan revision approved before the inspection. Minor field adjustments that still meet code are typically fine, but significant changes require formal revision. Having the plans ready shows professionalism and speeds the inspection.

Many jurisdictions require a pressure test on new supply lines (typically 80–100 PSI held for 15–30 minutes with no pressure drop) and a water test or air test on new DWV piping (fill the system with water to the highest vent and check for leaks, or pressurize with 5 PSI air for 15 minutes). Have the appropriate test equipment ready: a pressure gauge for supply testing, test plugs for DWV testing, and an air compressor if doing an air test. The inspector watches the test or checks the gauge — they don't supply equipment.

After passing the final inspection (post-drywall, fixtures connected and operational), request the signed permit card or final inspection report. Some jurisdictions post this online; others mail it. This document proves the work was inspected and approved — you'll need it when selling the home, filing insurance claims, or if a future contractor questions existing work. Keep it with your home's permanent records. The permit is not 'closed' until final inspection passes — an open permit on your property can complicate sales.

Store the approved plans, permit card, and final inspection report in your home file. Notify your homeowner's insurance company of significant plumbing upgrades (re-pipe, water heater replacement, sewer line replacement) — this may affect your coverage or qualify you for premium discounts. Some insurers offer 10–15% discounts for whole-house re-pipes or polybutylene replacement. At minimum, the documentation proves proper installation if you ever file a water damage claim.