Quick Answer
A running toilet usually means water is continuing to move from the tank into the bowl or overflow instead of shutting off normally. Common causes include a worn flapper, an incorrect water level, a fill valve that is not shutting off, a chain issue, or a damaged flush-valve sealing surface.
Common Symptoms
- •Water runs continuously after flushing
- •You hear the tank refill every few minutes
- •Water ripples in the bowl when nothing was flushed
Possible Causes
- •Worn or warped flapper
- •Fill valve set too high — water spills into the overflow tube
- •Flush valve seat pitted or scaled
- •Chain too tight or too loose
Safe Things You Can Check
Take off the tank lid and watch the water level. If it's above the overflow tube, lower the fill valve float.
Turn off the supply valve, mark the tank level, wait 15 minutes. If it drops, the flapper is leaking.
Feel the flapper — if it's slimy, warped, or cracked, replace it (a $5 part).
WHEN TO CALL
If a new flapper and fill-valve adjustment don't stop the running, the flush valve seat may be corroded and need a full flush valve replacement.