You can fix this
Likely cause: not enough water in the tank
A tank that fills well short of the overflow tube does not have enough water for a full flush. Raise the float.
Why this happens
Korky says that if the float is set too low there will not be enough water in the tank, which causes a weak flush. HomeTips lists low tank water as the first cause of a weak flush. Korky's target is a water level 1/2 inch below the overflow tube opening.
How to fix it
- Find the float adjustment: a screw or clip on a float cup, or a rod on an older ball float.
- Raise the float a little and flush.
- Let the tank refill and check where it stops. Aim for 1/2 inch to 1 inch below the top of the overflow tube.
- If it will not fill that high, or it takes a long time to refill, check that the toilet's supply stop is fully open. If it is, the fill valve may need replacing.
When to stop. If raising the float makes the water spill into the overflow tube and keep running, see the running toilet troubleshooter.
If this does not fix it, tell the plumber
- The tank fills well below the overflow tube.
- Whether raising the float changed the level.
- Whether the tank is slow to refill.
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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