Yes, a leak can hide under a bathtub for a long time. Water can escape from the drain connection, the overflow pipe, the supply lines, or gaps in the caulk and seep into the floor below without showing up in the bathroom.
Where Tub Leaks Start
- The drain: the seal between the tub drain and the pipe below can loosen or wear.
- The overflow: the opening below the faucet has a gasket that can fail, leaking when the tub is filled high.
- Supply pipes and valve: pipes inside the wall that feed the faucet can drip down behind and under the tub.
- Caulk and grout: gaps let shower water run behind the tub wall and onto the subfloor.
Clues Below the Bathroom
Because the area under a tub is hidden, you may notice the effects before the leak itself. Look for stains or sagging on the ceiling below the bathroom. Check for loose or cracked tiles near the tub, soft flooring next to it, or a musty smell. Paint peeling on the wall next to the tub can also be a clue.
A Simple Test
Fill the tub partway and let it sit. Check the ceiling below. Then drain it and check again. If the stain grows while the tub drains, the drain connection may be leaking. If it grows when the tub is filled very high, the overflow may be to blame. If it appears even when the tub is not used, a supply pipe may be leaking.
Getting to the Leak
Some tubs have an access panel on the wall behind the faucet end. If not, a plumber may reach the pipes from the ceiling below or the wall behind. Finding the exact source first keeps the opening small.
If you see signs of a tub leak, pinpointing the leak under the tub helps avoid tearing out tile. For bathroom plumbing questions, you can ask our plumbers to inspect the tub area at (833) 603-1840.