You can fix this
Likely cause: a chain that keeps the flapper from sealing
A chain that is too short holds the flapper open a little; a tangled one can get caught underneath it. Adjust it to a small amount of slack.
Why this happens
The flapper can only seal if it drops flat onto the flush valve. A chain pulled tight holds it slightly open, and a long chain can fold under the edge. Korky recommends leaving only 1 to 2 chain links of slack.
How to fix it
- Turn off the toilet's supply stop and flush to empty the tank so you can see clearly.
- Unhook the chain from the handle arm and move it to a link that leaves 1 to 2 links of slack with the flapper closed.
- Trim or tuck any long tail so it cannot fall under the flapper.
- Turn the water back on, flush, and repeat the dye test.
If this does not fix it, tell the plumber
- The chain was tight, tangled or caught under the flapper.
- Whether the toilet still runs after adjusting it.
Build the full list: what to tell the plumber.
Start this troubleshooter over
References (every fact above comes from one of these pages)
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