Stop Running Toilets From Wasting Your Water

An open toilet in a white bathroom.

Running toilets are not only noisy and annoying, but they are also wasteful, too. Fixing a running toilet is usually a simple, inexpensive fix any homeowner can do.

Why Is Your Toilet Running?

A running toilet is usually the result of one of two things: a poorly functioning ball-cock valve or flush-valve assembly. To find the source of your running toilet problem, take a look inside. Remove the top cover from the toilet, then flush and see what happens.

If the water runs, but does not fill up the tank, the flush-valve (stopper ball) at the bottom of the tank is the problem. To replace the stopper ball, turn off the water to the toilet tank. The shut-off is usually located behind and below the toilet tank. Flush the toilet.

  1. Unhook the guide wires or chains that attach the stopper ball to the handle assembly. Remove the old, faulty stopper ball.
  2. Set the new stopper into place on the valve seat. Slide the collar back down the overflow tube and center over the ball. Secure the collar to the ball.
  3. Attach the ball chain to the handle arm, leaving half an inch of slack on the chain. Test the assembly and replace the toilet cover.

How to Fix It

A running toilet can also be the result of a toilet tank that is overfilling, pouring water down the overflow tube. In a properly functioning toilet, the tank will stop filling about three-quarters of an inch below the top of the overflow tube. When you watch the internal mechanism of your toilet work, if water fills to the top and over the over-flow tube, the ball-cock assembly (float and arm) are the likely culprit. To test this, lift up on the float arm. If the overflow stops, the float assembly needs to be adjusted or replaced.

A float may malfunction if it is cracked and filling with water. The heavy ball does not rise high enough to lift the lever and stop the filling action. To fix a cracked ball-float, simply unscrew the ball (counterclockwise) from the end of the float arm and screw on a new float.

If the ball-float is intact, bend the float arm slightly and flush the toilet. If the tank fills properly, the problem is solved. If the tank continues to overfill after these measures, the washers on the ball-cock assembly are probably worn and need to be replaced. Turn off the water to the tank. Disassemble the ball-cock from the lever. Remove and replace the washers. Put the assembly back together and flush.

A toilet that is still overflowing after these measures needs a new fill valve. Purchase one and install according to the instructions provided by the manufacturer.

Most problems with running toilets are quickly fixed by troubleshooting and following these steps, or replacing inexpensive, internal mechanisms improperly functioning from wear after repeated use. Persistent problems that cannot be remedied may require consulting a licensed plumber.