If you have a leak in the bathroom, check the toilet first: water around the base, a toilet that runs or refills on its own, a damp supply line, or a stain on the ceiling below all point to a toilet leak. Each has a simple test that tells you which part is failing. Toilets are one of the most common sources of bathroom leaks, and the most likely places are the flapper, the wax seal at the floor, the supply line and the tank bolts.
Toilet leak points and how to check them
The flapper (silent leak)
A worn flapper lets water seep from the tank into the bowl, so the toilet refills on its own or runs intermittently. Add food coloring to the tank and wait 15 to 30 minutes without flushing. Color in the bowl confirms the flapper is leaking. This wastes water but does not usually damage the floor.
The wax seal at the base
If water appears around the base after flushing, the toilet rocks, or the floor near the toilet is soft or stained, the wax ring between the toilet and the drain may have failed. This kind of leak can soak the subfloor and stain the ceiling below.
The supply line and shutoff valve
Feel the braided or plastic supply line and the valve behind the toilet with a dry paper towel. Drips here leak constantly, whether or not the toilet is used.
The tank bolts and tank-to-bowl gasket
Water under the tank, especially after flushing, can mean loose bolts or a worn gasket between the tank and the bowl.
Condensation
On humid days a cold tank can sweat and drip onto the floor. If the water disappears when the weather changes, condensation may be the cause rather than a leak.
Signs the leak is not the toilet
If the toilet tests clean, look at the shower or tub, the sink and the pipes in the wall. A room-by-room approach is covered in do you have a leak in the bathroom?
What to do
- Close the toilet’s shutoff valve if water is leaking onto the floor.
- Stop using a toilet that leaks at the base until it is repaired; every flush sends water into the floor.
- Watch the ceiling below an upstairs toilet for stains.
More on silent leaks: how to detect a silent toilet leak and why your toilet keeps running. If water is reaching the subfloor or ceiling and you are not sure where it starts, see bathroom leak detection or call 1st Response Leak Detection at (619) 374-8554.