How to Fix a Running Toilet

Tips on how to troubleshoot and fix a constantly running toilet.

You hear the flow of water in and around the toilet. A quick check of the toilet bowl shows that the toilet flushed successfully. So why is the water running and how do you stop a toilet from running all the time?

The first thing you will need to do is troubleshoot and determine the cause of the running water. Find the shut off valve. This valve controls the flow of water from the water supply to the toilet tank. Usually it is found underneath the toilet tank and connected to a water supply pipe. Turn this valve off and flush the toilet once again.

Remove the top cover of the toilet tank. Wait for the water to drain. Look for a flap like piece of rubber in the bottom of the toilet tank. This flap controls the flow of water from the tank into the toilet bowl. Inspect the flap carefully. If a full seal is not made between the opening in the bottom of the toilet tank and the flap, the tank never fully fills and thus the water never stops running.

Push the flap back down over the seal. If it seems warped or cracked you'll need to replace it. Inspect the chain that connects the flap to the control arm. If you can't push the flap back down flat on the bottom of the toilet tank chances are the chain is too tight. Disconnect the chain from the control arm and reattach it on another chain link making the chain slightly looser.

If the flap and chain appear fine it's time to move onto the toilet floater ball. This ball (sometimes bulb or oval shaped) floats on top of the water surface in the tank. When the toilet flushes the ball drops and rises as the water level rises. Once the ball's floater control arm connected to the water pipe in the tank is level the water stops flowing. But if the ball control arm is bent or stuck the water continues to flow.

Lift the ball back up so that the control arm is parallel to the the top of the toilet tank. You may need to gently bend the control arm to get the ball in a good level position. With the tank cover off turn the shut off valve back to the open position and flush the toilet.

Carefully watch the floatation ball as it rises. Where does it stop when the water shuts off? Does the water keep running? Double check the flap seal and then gently bend the floater ball control arm slightly. Use the water mark lines on the sides of the tank as a good indicator of where the water should stop.

Test the flushing again to ensure the water level stops where the water marks are. If the ball is too high then the water may overflow out of the tank. Too low and the water pressure may be low or may continue to flow.