Noise in Pipes When Flushing Toilet – 5 Possible Causes

Written by

Paulk Webb


Freddie J. Hagopian

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noise in pipes when flushing toilet

If there is pipe noise when flushing toilet in your residence, consider this a warning sign of a problem that, if left unattended, could become more serious. Homeowners frequently worry about groaning pipes, and this article can help you identify their causes and potential fixes.

Most commonly, water hammer, high water pressure, a bad washer within the fill valve, a dirty valve, and a clogged drain are to blame for noise in pipes when flushing toilet.

What’s Causing the Noise?

#1 Water Hammer

Pipes make noise when water, and occasionally gaseous components, stop traveling abruptly along the drainline after they are just moving swiftly. This creates water pressure or waves that hits against the wall of pipes, causing the pipes knocking sound you hear.

The easiest way to fix noisy pipes when the toilet flushes is to remove gas and water from the air chamber in your toilet. Consider the following procedures to clear air in pipes and stop water hammer.

  • Find the toilet shut-off valve and fully turn it clockwise to halt the water from flowing to your toilet.
  • Keep the water running from all of your bathroom taps and open the flush valve on your toilet to initiate the flushing process.
  • Close all of the faucets before turning the shut-off valve to restore water flow.
  • Flush the toilet a second time. You can determine whether there is still residual toilet noise after flush by doing so.
  • If noise from pipes is still observable, another factor might be the cause behind the loud vibrating noise from your toilet.

#2 High Water Pressure

groaning pipes

When a toilet receives more water pressure than it can handle, or over 60 PSI, there is a high tendency for a toilet makes a loud noise such as clicking in pipes.

Using a water pressure gauge to check the water pressure in your toilet is the best preventative strategy for this condition. An inexpensive $10 gauge may already help you avoid noisy toilet problems that might end up costing you more to fix.

  • Find a hose bib attachment to secure the water pressure gauge.
  • Let the device perform its task and read the pressure value indicated.
  • If the reading exceeds 60 PSI, install a pressure regulator at the main water line of your home.

#3 Defective Fill Valve


Noisy water pipes may result from a defective fill valve, specifically, its diaphragm that controls the water level in the toilet tank. When this component stiffens, you can either repair the fill valve or better, replace it entirely to quiet a loud flushing toilet.

  • Replace the fill valve, which will cost you around $15-$40, depending on the toilet model and other considerations.
  • Temporarily disconnect the supply of water.
  • Empty the toilet tank and open it to locate the fill valve.
  • With pliers or a wrench, turn the valve’s nut counterclockwise to release it from the water supply line.
  • Install the new fill valve for the toilet.
  • Tighten the nuts connected to the valve, reattach the water supply line, and turn the water back on.
  • Make sure that the valve’s float is approximately 1 inch (2.5 cm) underneath the top of the overflow pipe.

#4 Filthy Valve

Fog horn noise from toilets may indicate a dirty valve. Be sure to always have your toilet components cleaned to avoid the emergence of pipes squeal.

  • Turn off the water supply.
  • Access the valve, clean any sections that are reachable, and make sure the dirt is emptied from the tank.
  • To determine if the noise has subsided or not, flush your toilet as usual. Keep an ear out for pipes rattle when flushing the upstairs toilet or any toilet in your home.
  • Should the problem remain as is, consider replacing your valve.

#5 Clogged Drain

If you hear toilet flush downstairs or from another floor of your home, this could be a sign that a drain is clogged.

Blockage may happen when you flush paper towels, hair, or even food down the toilet.



Why do my water pipes sing when I flush the toilet?

When you flush the toilet, a loud sound may come from the pipes. This loud sound may be caused by a water hammer (i.e, when the toilet fill valve closes and water stops flowing abruptly).

Other typical toilet issues include a blocked drain, a worn-out valve that needs to be replaced, or unchecked water pressure.

When I flush the toilet the pipes make a loud noise?

It is no longer uncommon for homeowners to hear a loud noise when they flush the toilet. This occurrence may result from a fill valve with an old metal ballcock mechanism, loose pipes, and other causes we mentioned above.

How do I stop my pipes from banging when I flush the toilet?

Depending on the issue that is causing your pipes to bang, different actions may be taken to stop them.

For water hammer problems, simply clean out the air chamber; for filthy or damaged fill valves, clean or replace them.

For clogged drains, clear out the unwanted waste using a toilet snake; and for high water pressure, use water pressure equipment to monitor it and keep it regulated.


At first impression, noise in pipes when flushing toilet might not seem like a significant issue. However, that is absolutely not the case. No matter how minor this problem may appear, it is always preferable to have it fixed as soon as possible rather than waiting until it becomes more problematic.

Therefore, if your toilet makes loud noise, be concerned. Consider the information in this article as you search for potential causes that could result in it. Once you identify the issue, follow the above instructions to solve it promptly and avoid the worst-case scenario.

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