How do I fix a running toilet?

A running toilet is usually caused by a few simple issues inside the tank. Before you start, turn off the water supply valve located behind the toilet (turn it clockwise) and flush the toilet to empty the tank.

Here are the three most common culprits and how to fix them:

1. The Flapper Valve

The rubber flapper at the bottom of the tank may not be sealing properly, allowing water to leak into the bowl.

• Check: Look for debris or mineral buildup around the seal. If it’s warped or brittle, it needs to be replaced.
• Fix: Clean the rim where the flapper sits. If that doesn't work, take the old flapper to a hardware store to match the size and replace it.

2. The Float Height

If the water level in the tank is set too high, it will constantly spill into the overflow tube (the open-ended pipe in the center of the tank).

• Check: Look at the water level. It should be about an inch below the top of the overflow tube.
• Fix: Adjust the float. Depending on your toilet type, this usually involves turning a screw on top of the fill valve or sliding a clip on the float arm downward to lower the water level.

3. The Chain Length

If the chain connecting the flush handle to the flapper is too short, it keeps the flapper from closing. If it's too long, it can get caught under the flapper.

• Check: Ensure there is a little bit of slack (about 1/2 inch) in the chain when the handle is at rest.
• Fix: Adjust the chain length by moving the clip to a different link.

When you’re finished: Turn the water back on, let the tank fill, and see if it stops running once the water reaches the appropriate level. If the toilet continues to run after checking these three things, you may need to replace the entire fill valve assembly.