Bathroom Remodel Plumbing in Nashville: What Permits You Actually Need

Cosmetic bathroom work doesn't need a plumbing permit. Almost anything else does. Here's where the line falls in Davidson County.

The Permit Trigger Line

Metro Nashville-Davidson County requires a plumbing permit any time the work alters the plumbing system. That includes:

• Moving a fixture to a new location.
• Adding a new fixture (a second sink, an extra shower, a bidet).
• Replacing pipe or running new pipe inside walls.
• Replacing a water heater.
• Changing a tub for a shower or vice versa.
• Cutting into the drain or vent system.

What doesn't require a permit:

• Swapping a faucet, showerhead, or toilet for a new one in the same location with no pipe changes.
• Replacing a vanity countertop while keeping the existing sink.
• Cosmetic work — tile, paint, mirrors, lighting (lighting may need an electrical permit).

Why Permits Matter

Three reasons not to skip:

• Inspection catches problems. Inspectors check that fixtures are properly vented, drains are correctly sloped, supply lines are sized right, and the install meets code. That's a free quality control check.
• Resale and disclosure. Many real estate transactions in Davidson County ask about permitted vs. unpermitted work. Unpermitted plumbing work can complicate the sale or force a retroactive permit.
• Insurance. If a water leak from unpermitted work damages your home or a neighbor's, the insurance claim can be denied.

Who Pulls the Permit

In Nashville, plumbing permits are usually pulled by a licensed plumber. The plumber's license is what authorizes the permit to be issued. Homeowners can pull permits for work on their primary residence under some circumstances, but the inspection and code compliance is still required.

If a contractor offers to do bathroom plumbing work without pulling a permit, that's a warning sign. Walk away.

What the Inspector Checks

Rough-in inspection (before drywall) looks at:

• Pipe materials and sizing for each fixture.
• Drain slope (1/4 inch per foot for most residential drain lines).
• Venting for each new fixture — either a stack vent, AAV, or proper wet venting.
• Shut-offs at the appropriate locations.
• Pressure test on the new supply lines.
• Drain test on new waste lines.

Final inspection happens after fixtures are installed and looks at:

• Trap installations on each fixture.
• Proper sealing at flanges and connections.
• Functional drainage and supply at each fixture.
• Water heater venting and shut-off (if changed).

Typical Bathroom Remodel Plumbing Scope

For a moderate Nashville bathroom remodel, the plumber's work usually breaks into three phases:

Demo phase

Disconnect and remove existing fixtures. Cap supply and drain lines for safe demolition.

Rough-in phase

Run new or modified supply and drain lines to the new fixture locations. Set the tub or shower pan, drain assembly, and any in-wall valves. Inspector visits.

Trim phase

After drywall, tile, and cabinetry are in, install the toilet, sinks, faucets, showerhead, and shower trim. Connect everything, test, and call for final inspection.

Hidden Issues That Show Up Mid-Project

Common surprises in Nashville bathroom remodels:

• Rotted subfloor under the existing toilet or shower — needs replacement before new fixtures go in.
• Failed cast iron drain pipe in older homes — section replacement adds to the scope.
• Undersized vent on the existing stack that won't serve the new fixture count.
• Galvanized supply lines that need to be replaced from the demo point back to a usable connection.

A good plumber walks the project before quoting and flags likely surprises so they're not surprises mid-project.