Why Your Pipes Are Making Loud Noises

While those banging or knocking noises from your pipes indicate a problem, the issues vary in severity, and some are not always as detrimental as one might think. In this blog, we’ll cover the common causes of noisy pipes.

But first things first: when are you hearing the noises? Pinpointing when those sounds occur can help you diagnose the problem.

Do the sounds occur:

  • while you’re running cold water?

  • while you’re running hot water?

  • when the hot or cold water supply is shut off?

  • or at seemingly random times?

Each indicates a separate problem that we’ll expand upon below.

Pipes Making Noise While Running Cold Water

If you hear a banging or knocking noise coming from the sink or from the pipes in the wall when you start running cold water, this most likely indicates that the cause is high water pressure. What you’re hearing is the sound of the pipes striking walls or other pipes as water rushes through them too quickly.


You may be able to diagnose this issue on your own by checking your home’s water pressure with a pressure test gauge. The ideal pressure for your house should range between 40 and 80 PSI. If the pressure is higher than this, contact a plumber so that your house’s PRV (pressure reducing valve) can be fixed or replaced.

Pipes Making Noise While Running Hot Water

Do you hear a knocking or clicking noise only shortly after you turn on hot water? Does it not stop right away after you turn the hot water off? This probably indicates that your home has CPVC (chlorinated polyvinyl chloride) water lines supplying it hot water and that those water lines--unfortunately--were not installed well.

CPVC pipes expand when hot water flows through them. If the plumber who installed them does not leave enough room around the piping for it to expand, then the pipes will knock against whatever is right next to it each time you turn on hot water.


Fixing this problem will involve not only locating which pipes are making the sounds but also giving those pipes more room to expand. Opening up parts of one or more walls and possibly moving the CPVC piping might be necessary. Rather than cutting walls and pipes on your own (not recommended), you’ll probably want the expertise of a plumber.

Noises When the Hot or Cold Water Supply Shuts Off

Do you hear a knocking sound in the laundry room each time your washer stops filling with water? Maybe you hear a knocking sound in your bathroom walls whenever you flush the toilet.

If these sorts of things are occurring, a water hammer is probably the culprit. Somewhere in your piping, there’s a water valve that’s shutting off so suddenly that the water that was running ends up “hammering” into it, and the impact is shaking your pipes.


Newer homes have been built with water hammer arrestors to prevent the occurrence of water hammers. If you have a newer home (built after the 1960s), it may be that one or more of your arrestors has stopped working properly. If your house was built prior to the 1960s, the pipes were constructed with shock-absorbing, T-shaped air chambers. Water can eventually move the air in those chambers, at which point you’ll probably have to drain all the water out of the plumbing and refill it.

Regardless of your home’s age, it’s important to get this issue fixed quickly because particularly forceful water hammers can dislodge pipes and create leaks.

Pipes Making Noises at Seemingly Random Times

If you’re hearing banging noises at random, even while no water is running, it’s likely that there’s some sediment buildup at the bottom of your water heater. If this is the case, what you’re hearing is the resulting reverberations of steam bubbles coming out of that built-up sediment.


To fix this problem and get rid of the sediment build-up, you or a plumber will need to flush your water heater.

If you’re hearing loud noises coming from your pipes, you can always contact one of our respectful and courteous plumbers at EZ Flow Plumbing, LLC for an expert opinion and a professional repair job. Our licensed plumbers are not only focused on providing you with our exceptional technical skills but with industry-leading customer service.

Contact us online to request a service!

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