Why Is My Toilet Making a Vibrating Noise After Being Flushed?

2016 May 24
Posted in: Plumbing

Do you hear a loud vibrating noise for about 30 seconds after your flush your toilet? Does the sound reverberate through your plumbing like the noise is coming from the pipes in your walls or floor?

It may even be more of a humming noise like a fog horn.

The culprit of the vibration is likely your toilet fill valve.

How a bad toilet fill valve creates a vibrating noise

The toilet fill valve is located inside your toilet tank, and it’s the part of the toilet responsible for refilling the tank with water after you’ve flushed.

Parts of a Toilet Tank
The parts of a toilet tank. Yours may look slightly different but should have the same parts.

Here’s how the fill valve works:

  1. Water comes into the fill valve from the bottom and out through the fill tube.
  2. Water in the tank gradually rises, lifting up the float on the fill valve.
  3. The raised float shuts off the flow of water by pushing down on a small diaphragm inside of the fill valve. 

The diaphragm is made out of a pliable material (usually rubber), which when pushed down acts as a great seal.

But, over time, that diaphragm can harden and become stiff. So instead of forming a tight seal, the incoming water bounces the hard diaphragm around inside the fill valve, creating the vibrations you hear.

The fix: replace the fill valve

While you could try to replace the diaphragm inside the toilet fill valve, it’s usually better to replace the entire fill valve since they’re not that expensive. 

If you have noticed your toilet vibrating randomly (without anyone actually flushing it), then you should also replace the flapper

Flappers are made of a rubber-like material that can also deteriorate over time, especially when exposed to cleaning chemicals. And a deteriorated flapper will allow water to leak into the toilet bowl, slowly draining the tank. The tank will then refill (leading to the vibrating noise).

Instructions for replacing these toilet parts are included with the packaging of the parts. Or, if you’re uncomfortable doing it yourself, you can always hire a plumber.

Toilet still making weird noises?

In the Phoenix area? Have a trained and licensed George Brazil plumber find and fix the problem for you.

George Brazil Plumbing & Electrical has been serving Phoenix-area homeowners’ plumbing and electrical needs since 1955.