Shhhh! Quieting Noisy Plumbing

Those strange sounds you hear around the house, especially at night – creaks, clanks, whistles, bangs, squeals – can have many sources: Normal house settling. Pets creeping around bumping into things. Kids being kids. Maybe even a ghost or two causing havoc?

Or it might be a case of noisy plumbing, which can be just as scary and disturbing as any of those scenarios – because if not dealt with, the underlying issue that generates the noise will only get worse and could result in expensive repairs.

Noisy pipes can be caused by different things. For plumbers trying to diagnose the problem, recreating the noise is often the hardest part and involves a variety of tests, including turning valves on and off, testing water pressure, listening to walls (sometimes with stethoscopes), running water through pipes, and flushing.

Several situations can cause noisy plumbing. Here are a few:

Water Hammer

When running water is suddenly shut off, the liquid has nowhere to go and slams against the shut-off valve. The loud thud that follows is known as water hammer. If left untreated, it can be not only noisy but also potentially damaging to joints and hoses.

To eliminate water hammer, simply install water hammer arresters at each location of the noise. (You may discover that you solve one only to hear another you didn’t notice earlier.)

In older homes, you may need to shut off the main water, open all the faucets, and drain the entire house from the lowest faucet. After you restore the water, the air will be pushed into the risers, temporarily preventing water hammer, as the risers will become waterlogged again. You can also install water hammer arrestors. This is not necessary in homes with newer plumbing, as today’s air chambers are sealed (water hammer arrestors that do not become waterlogged). They are installed in key locations in the plumbing system during construction.

Loose Pipes

Sometimes large volumes of water moving rapidly through a pipe will cause it to sway and come loose from the straps holding it into place. Once you have determined the exact location of the loose pipe (by running water or flushing the toilet and listening for the rattling), you can tighten the straps. Unfortunately, the pipes occasionally might be located inside walls and you’ll need to open the walls to silence the noise.

High Water Pressure

If the water pressure is too high, it can cause noisy pipes as well as damage to appliances such as the dishwasher or washer. Test the pressure to determine its exact level. Installation of a water pressure regulator or a pressure-reducing valve should take care of this issue. Ideal pressure should not exceed more than 80 psi; 45 psi is the usual factory setting for pressure regulators and they are usually adjustable to suit specific needs. You should add an thermal expansion tank at the water heater as you have closed the water system and without it, your pressure can build to a temporary level that may burst flex lines or cause your temperature and pressure relief valve to leak.

Worn Out Washers

If the washer on a valve is not tight, it can cause the water to oscillate as it flows by, which can cause whistling or squealing. Diagnose it by turning the washer to different positions to determine whether that eliminates the noise. If not, or if the washer is completely worn out, replace it.

Note: A worn out washer on the main shut-off valve can cause other valves to be noisy. Be sure to check there when diagnosing.


If a flapper is leaking in a toilet, the fill valve will continually try to fill the tank up, causing the noise of running water in the toilet. Changing the flapper often eliminates that problem. However, if the flush valve seat is worn or has nicks or flat spots, it will need to be replaced as well.

Another noisy issue occurs with older toilets, in which the buoyancy of the fill valve’s float ball determines when the water will shut off. At the point just before it shuts off the water, it can make a whistling noise. You can either change the ball so it’s more buoyant or change the washer so it’s more pliable and shuts off the water sooner.

Drain Lines From Upper Floors

Water moving down and out into the sewer system can be a noisemaker, even when operating properly. The best solution is to either replace with cast iron pipe or surround the plastic pipes with insulation. That won’t completely eliminate the sound, but it can muffle it enough to make it less irritating.

You may also be interested in these related items:

return to top ↑

Copyright© 1995-2024
All Rights Reserved.