There are 3 potential reasons why you may be hearing a rattling noise after you flush a toilet in your home.

  1. A water hammer problem (more about this later on)
  2. A water pressure problem - it may be set too high
  3. A problem with a water pipe that has gotten loose

Any one of these 3 issues (or a combination of any of them) could be the cause of the noise you are hearing.

The Water Hammer Problem

The term "water hammer" in a toilet refers to the noise and/or vibration that is produced when running water hits a closed valve - which is supposed to be an open valve. When the water hits that closure, and essentially has nowhere to go it creates a loud thud and/or vibration. Water hammers could also be caused by washers that are worn or damaged.

We recommend that you do not ignore a water hammer problem. In time, they could cause some serious damage to your water pipes.

How Do You Stop Water Hammer After Flushing The Toilet?

The best way to fix this problem is to install (and or repair) a product called a water hammer arrestor. This usually looks like a pipe that is located close to a fixture. Your plumber can help you locate it, fix it and/or install one for you.

But, you may want to try these 10 steps which may fix the water hammer problem with your toilet.

  1. Turn off the main water supply to the house.
  2. Turn on all your cold water faucets, starting with the faucets at the highest level of the house (2nd or 3rd floor). Do not turn them off.
  3. Let all the water drain from your faucets.
  4. Flush all the toilets in your house.
  5. Wait 30 minutes.
  6. Turn the main water supply back on.
  7. Wait 10 minutes to allow all the faucets to start running again.
  8. Turn off all these cold water faucets starting with the lowest level of the house (main floor or basement).
  9. Your toilets should automatically refill.
  10. Once all the faucets are turned off - flush all your toilets again. Listen for the water hammer effect.

If you follow this process and still feel the vibration or hear the loud knocking that the hammer effect creates, we recommend you call in a professional plumber to assess the problem.

Water Pressure Problem

Here in Georgia, water pressure regulators are now required by code to be installed in homes. These devices control the incoming water pressure and keep it from getting too high or too low.

Your water pressure should not be higher than 80 psi.

You want to avoid high water pressure for several reasons:

  • It may cost you about 2x as much on your water bill
  • High water pressure can put excessive wear and tear on your pipes
  • It has been shown to decrease the lifespan of your appliances such as dishwasher, washing machine and water heater.

If you want to test to see if your water pressure is the cause of your noisy pipes you can purchase a threaded pressure gauge.

Problem With Loose Pipes

It makes sense that older pipes can become loose after years of use. If they are strapped down anywhere, the strapping can break. If they were improperly placed too close to a wall or other structure and now they are loose they can easily bang against that structure when the pressure of the water is running through them.

Finding the loose pipe is step number one and then of course, correcting the issue either by replacing the strap or using wire or insulation or foam padding is step number two in reducing any noise due to this issue.

Of course, there may be an odd reason that is unique to your home and your noisy pipe but in general, these are the 4 most common reasons that you are hearing those loud noises.

If you have any questions about noisy pipes or are having some problems with it, call Atlantis Plumbing today at 770-443-8229. We are available 24 hours a day, 7 days a week.