How do you stop the toilet tank from filling with water?

4Check if the water in the tank is at the water line. Not having enough water in the tank will have the toilet run. If the water is NOT at the water line, check your water valve to see that it is on all the way.

If it is NOT, turn it all the way on and your tank should start filling up to the water line (unless the Refill Valve or Float are not adjusted correctly). Try this BEFORE changing flapper or anything else. 5Adjust, Clean or Replace the Refill Valve &/or Float.

The toilet may not stop running and water may be running over the top of the overflow tube even though the flapper is closed and the tank is full. First try adjusting the valve and float. Pull up on the float with your hand.

If this action stops the flow, then adjust the level of the float so the tank stops filling when the water is about an inch (2.5cm) below the top of the overflow tube. If the tank level is too high, the excess pressure can cause water to leak through the flapper into the bowl (even with a brand new flapper). If the float is around the valve post, pinch the metal clip and slide the float down on the wire.

If the float is a ball on an arm, try turning the small screws on top of the valve.