Fix a Running Toilet
A toilet that keeps running often comes down to a flapper, chain, or fill-valve adjustment. Start with a simple inspection before buying replacement parts.
Close the toilet supply valve before replacing parts. Do not force a stuck valve or overtighten fittings against porcelain.
Step-by-step instructions
- 1
Find where water is going
Remove the tank lid carefully. Check whether water is flowing into the overflow tube or escaping through the flapper at the bottom of the tank.
- 2
Inspect the chain and flapper
Make sure the chain is not holding the flapper open. Allow a little slack. Look for hardened rubber, debris, or a flapper that no longer seals.
- 3
Check the fill level
Adjust the float according to the fill-valve instructions so water stops at the tank’s marked fill line and remains below the overflow tube.
- 4
Replace a worn part
Shut off the supply and flush to empty the tank. Fit a compatible flapper or fill valve according to its instructions. Keep seals clean and tighten only as directed.
- 5
Flush and recheck
Restore the supply, let the tank fill, and flush several times. Confirm the fill valve stops and inspect the floor and supply connections for leaks.
Watch the project
Frequently asked questions
Why does it run only occasionally?
A slow leak past the flapper can lower the tank level and trigger a refill. Check the flapper seal and chain first.
