Why is Your Toilet Hissing?

If your toilet makes a hissing noise, it means you likely have one of the following problems:

Debris that is stuck in the fill valve
A broken float

We will explain these two problems, why they create your toilet’s hissing sound, and what to do about it.

If you need a plumber to fix your toilets hissing sound immediately, call us and we will send a plumber out to you.

Problem number one- debris stuck in the fill valve.

The fill valve is a part that is near the left side of your toilet tank. The valve works to fill the toilet tank with water after each flush. When it works properly, the fill valve will shut off as soon as the water in the tank reaches a certain level.

The fill valve can stop working right if debris gets caught in it. The debris will keep the valve from closing correctly. It also pushes rough a restricted opening and that causes the hissing noise

To fix the issue, remove the valve and let any dirt get flushed out of it. If you notice that it is broken, follow the steps in the video below to replace it. If you cannot do this yourself hire a plumber to flush any sediment out of the fill valve.

Problem number two – the damaged float

The toilet’s float indicates to the valve when it is time to turn on or off. It does this by going up and down. After the toilet gets flushed, the float raises upward and lets the fill valve go on. Once the float goes back to the correct level, it causes the fill valve to shut the water off.

Floats sometimes look like black or red balls or balloons. Older toilets have a long metal arm connected to the float. Newer toilets have a similar structure but may have a flap type of cover rather than a round one.

There are times where certain problems prevent the float from getting high enough to shut the fill valve all the way off. As water tries to escape, the pressure builds inside the valve trying to escape a small opening, which then creates a hissing noise.

Some of the problems that can prevent a float from shutting off include:

Water getting into the float thereby affecting its buoyancy
Debris blocking the float’s movement upwards

What you can do about this is hire a plumber to take a look at it and repair it for you.