Slow drains · Tub stoppers · Water downstairs
Tub & shower drain repair and leak diagnosis.
A tub has a drain at the bottom and an overflow near the top. A shower collects water at its floor drain. Below them, the drain connections and a water-filled trap carry wastewater away while blocking sewer gas from entering the room.
Under the tub
Drain. Overflow. Trap.
The tub drain and overflow join into one waste assembly before the tub’s trap.
Drain flange & shoe
The flange is the ring visible in the bottom of the tub. It joins the drain shoe—the elbow beneath the tub—with seals that keep bathwater out of the floor cavity.
Overflow & gasket
The upper opening receives water as the tub fills high. A gasket seals the overflow fitting against the tub. Deterioration or a loose fit can leak when water reaches this opening.
P-trap & drain branch
The curved trap retains a water seal. Its outlet joins the drain branch; the vent arrangement helps protect that seal as water moves through the drainage system.
Water around your ankles?
Start at the drain opening.
Hair and soap collect around a shower strainer or tub stopper, then build farther into the trap and branch. A stopper that barely lifts can also make a tub empty slowly.
We check the opening and stopper movement, clear the obstruction and run enough water to see how the drain handles sustained flow. Repeated backups call for a closer look at the branch. Several fixtures backing up together can point farther downstream.
The tub won’t hold water
A lift-and-turn, toe-touch or push stopper seals at the drain opening. Older trip-lever assemblies use linkage behind the overflow plate. We check the seal and travel, then adjust or replace the worn assembly.
Sewer smell from a rarely used fixture
A trap can lose its water seal through evaporation. A smell that returns after normal use deserves a check for a leaking trap, drainage or vent trouble. Hair and residue at the opening can create odors too.
The clue is when it gets wet
Trace the leak before opening more wall.
Stop using a fixture that is sending water into the building. Tell us what was happening when the leak first appeared; controlled testing helps us find the source.
- With every fixture off
- We start with the pressurized supply pipes, valve body and nearby water connections.
- While the tub or shower runs
- We separate the outlet piping, drain and splash paths, checking one at a time.
- When a full tub empties
- The waste fittings, trap and downstream drain carry their heaviest flow. Watching those joints can expose a leak hidden during a short test.
- When water reaches the overflow
- The overflow gasket and fitting become a key check.
- When walls or the curb get sprayed
- We check trim penetrations and the enclosure’s waterproofing with the remodel team.
Water can travel along framing before it stains a ceiling. The wet spot below is a starting clue; exposing the source may take access from the room behind the fixture or the ceiling beneath it.
The drain meets the shower floor
One connected water barrier.
A tiled shower manages water beneath its tile surface. The waterproofing layer has to join the drain as a complete assembly. A traditional liner and clamping drain handle that connection differently from a bonded membrane and bonding-flange drain.
Schluter’s KERDI-DRAIN, for example, has a broad flange that bonds to its waterproofing membrane. Choosing the drain and shower base together keeps their connection workable. During a remodel, the plumber and waterproofing installer coordinate the drain height, support and testing before tile hides the work.
Read more: Schluter: shower waterproofing and drain assemblies ↗
Useful answers
Common questions.
Can a tub overflow leak even when the tub drain is fine?
Yes. The overflow has its own fitting and gasket against the tub. A leak may appear only when bathwater reaches that opening or shower spray enters it.
Will resealing the tile fix water leaking downstairs?
The repair depends on where water escapes. A leaking drain fitting, supply connection or failed waterproofing layer needs work at that source. We trace the leak before choosing the repair.
Will you need to open the ceiling?
Access depends on the fitting and the house layout. An existing access panel or the room behind the tub may give us a route. A trap or drain joint between floors may need a ceiling opening so it can be repaired and checked.
Sources & public guide record
Maintained by Mountain Man Plumbing · Utah Master Plumber, Lic. #12992295-5501.
- Oatey: bathtub waste and overflow connections ↗
- Schluter: shower waterproofing and drain assemblies ↗
Version 2026.09.10.1 · References checked 2026-09-10.