How to fix a running toilet

A toilet that runs continuously or sporadically for no reason wastes a lot of water. It’s also a sign that your toilet needs maintenance or repair. A few simple tricks will help you determine the cause and stop your toilet from running once and for all.

1. Remove the lid from the tank and check to see if the chain is caught on anything. If so, it could be too long and in need of adjustment. The flapper at the bottom of the tank might also be warped or misaligned, which could signify that there is debris or an obstacle preventing it from sealing or that it needs to be replaced.  See my previous post for a diagram of the inside of a toilet.
2. Check the water level. When the tank is full, it should come to the water line or about an inch below the top of the overflow tube. One way to remedy a low water level is to raise the float by bending the float arm upward. On the other hand, if the water level is too high, it will slowly leak into the bowl, resulting in the need to refill. Make sure there are no obstructions to the float and make adjustments as necessary to attain the proper water level.
3. Check the float. When the toilet is running and filling with water, raise the float with your hand. If the toilet stops running, your float works but may need adjusting, raising or lowering it.  Or your float may be damaged and cracks or holes might be causing it to fill with water. In that case, you need to replace the float.
4. Check the ball valve and assembly for mineral deposits. Lime is often the culprit that keeps moving parts in the tank from functioning as they should. Descaling and cleaning them can break loose the impediments.
5. If you’ve tried everything and the toilet continues to run, it might be time to replace your refill valve assembly.