How to Replace a Toilet Fill Valve

deciding do I need to replace the fill valve

If you hear the toilet run and it's not shutting off, there is a good chance the problem lies with the fill valve. After learning to diagnose the problem, you will also learn how to replace a toilet fill valve. Before we start with the troubleshooting process, we need to begin with the basics.

What Is a Fill Valve?

As the name suggests, the fill valve controls the refilling of the toilet tank. So the next question you're probably asking is, how does a fill valve work? Typically, it works with a float ball or a cup, which rises with the water level. When it's down, the valve opens and fills the tank. The valve shuts close when the tank is full. It's pretty easy to tell if you have a float ball or a float cup. A cup is basically a part of the fill valve body, and the ball is usually attached to an arm that extends away from the valve.

Do I Need to Replace the Fill Valve?

Now that you know what you're looking at, how do you know you need to replace it? Start with the flapper. This is a cheaper part, it's easier to replace, and you may not even have to replace it. It may be in fine condition. There might be something obstructing the seal. Feel around the edges to look for a bend in the seal. Make sure the chain is not the culprit, as it sometimes gets in the way of the flapper.

If that didn't do the trick, then it's very likely the fill valve. In most tanks, if the fill valve is open and the ball valve is sealed, the excess water goes straight down the overflow tube.

Fixing a Broken Fill Valve in 10 Steps

The problem might be a float that needs adjusting, so tinker with that a little bit. The flapper may not be able to establish a seal because the float is causing problems. Move the arm around a little to see if there is a better configuration. If that still doesn't solve the problem, you're going to probably need to buy a new fill valve and replace the old one. Here is the process for how to change a fill valve (universal):

Close the shut-off valve.
Drain the tank by flushing it and soak up any excess water with a sponge.
Disconnect the toilet supply line.
Remove the existing fill valve (there is a nut under the tank that holds the valve in place) and lift it out from the tank.
Clean the area as needed.
Before installing the new valve, adjust its height so that the C. L. marking you see near the top is one inch over the overflow tube. You can adjust it by turning the shank.
Install it by reversing the process outlined in step 4.
Reconnect the toilet supply line and open the shut-off valve.
Insert the refill tube to the outlet near the top of the fill valve, and then connect it to the overflow tube.
Adjust the float cup by flushing the water out of the tank and turning the screw to raise and lower the water level to your desired height.

You should read the specific instructions that come with your valve assembly because there might be a little more to the process.

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