What is a Fill Valve in a Toilet Tank

When a person flushes the toilet, the flush lever pulls up a chain that is connected to the flapper. That allows water to rush out of the tank and into the toilet bowl. When water levels recede far enough, the flapper can close and water from the fill valve begins to flood the tank once again.

The fill valve knows when to start adding water because of a float that is installed in the tank. The float is like an on/off switch. When it reaches a high enough level, the fill valve turns off. When it dips below that level, the fill valve turns on.

What About the Large Tube in the Toilet Tank?

The modern toilet has an overflow tube that is connected to the toilet bowl, just like the flapper is connected to it. Should too much water be allowed into the toilet tank, the overflow tube provides a place for the extra water to escape. The primary cause for a toilet to need this feature is a float that is not positioned properly.

If you have a running toilet, check to see if you have a tank that is overflowing with water. Bend the arm of the float so that it can be in a lower position to fix this issue.

A fill valve can operate for several years without a problem, but like any other mechanical item, it can begin to fail. By recognizing the signs and symptoms of a fill valve that is not working properly, you can stop water loss immediately.