Diagnosis
- Remove the tank lid and watch.
- Is water flowing into the overflow tube? The refill height is wrong, or the fill valve will not shut.
- Is the tank refilling every so often? Water is leaking past the flapper.
- Does the handle stick? The chain may be tangled or too short.
Fixes
- Adjust the float leaving the water some 25 mm under the top of the overflow.
- Adjust the chain so it has slight slack when the flapper is closed.
- Replace the flapper if it is warped or stiff; see replacing a flapper.
- Clean or replace the fill valve if it does not shut off.
The dye test. Add some food dye to the tank water. Tint showing in the bowl a quarter-hour later, with no flush, convicts the flapper.
Hard water
Mineral deposits from Mississauga's moderately hard water can stop a fill valve from sealing. Flushing the valve by removing its cap and briefly running water often clears debris.
When to call
If parts are corroded, the tank leaks at the bolts, or the toilet keeps running after new parts, call for toilet repair. A blocked toilet that drains slowly may point to a drain issue; see hydro jetting for stubborn lines. Your water meter shows whether a leak is affecting your bill; see reading your water meter.
Worth knowing
Answers our Mississauga crew gives most
Is a running toilet really costly?
It can be a great deal, especially with a constant flow into the overflow.
Are toilet parts universal?
Many are, but check your toilet's flush valve size and brand.
Should I turn off the toilet's water?
Yes, if it runs constantly and you cannot fix it right away.