Why Your Toilet Keeps Running (And How to Fix It)

The Flapper Is the Usual Suspect

The rubber flapper at the bottom of the tank seals water in. Over time it warps or gets a mineral coating and stops sealing, letting water leak into the bowl continuously. Replacing it is inexpensive and quick.

Check the Fill Valve and Float

If the water level rises too high, it spills into the overflow tube and the fill valve keeps running. Adjusting the float or replacing a worn fill valve usually solves it.

The Chain and Handle

A chain that's too short holds the flapper open; too long and it gets caught underneath. A quick adjustment often stops the running.

When It's Not a Simple Fix

If you've swapped the flapper and adjusted the float and it still runs, there may be a crack or a supply issue worth having a plumber inspect.