Noisy Plumbing: Why Do You Hear Water Running Through Pipes?

It’s incredible how the faint noise of a gently dripping tap coming from down the hall in the bathroom can keep us awake at night. Even the quietest of noises can seem horrendous at 3 am when we’ve been lying in bed trying to get to sleep for hours.

So, it’s no wonder that a more serious plumbing-related noise can truly drive us round the bend.

Some plumbing noises are very distinctive and are caused by one of a handful of reasons. Others can be much harder to pinpoint and diagnose, making them more challenging to fix.

The rest of this article will present the most common problems, likely causes, and how you can fix them. So, read on to learn more about your noisy plumbing and whether you can fix it yourself or need the services of a professional.

What are Some Common Plumbing Noises Coming From Pipes?

Some of the most common types of noisy plumbing include:

• Hammering or banging
• Vibrations or humming
• Rattling
• Whistling or squealing noises
• Rubbing or ticking noises
• Metallic clinking noises

What Causes Noisy Plumbing?

Noisy plumbing can be caused by loose pipes, high water pressure, worn-out washers, and other issues. Hearing the water running through your pipes and making these noises doesn’t usually deserve an emergency call out, but if left unfixed, it can cause more severe problems down the line.

The Typical Sound of Water Flow

We should first discuss the typical sound of water flowing through your pipes.

This noise is often heard when you drain a sink, or your washing machine empties its drum. The noise of flowing water coming from your plumbing is often perfectly normal and needn’t indicate any kind of problem.

Particularly in older houses, it is common to hear flowing water as it travels along your pipes. Older homes often have exposed drainpipes that run along the basement ceiling, or perhaps they are underneath exposed floorboards with no carpet to absorb the sound of water running through them.

If you hear water flowing through these pipes, it is perfectly normal. Of course, you can reassure yourself that there is no problem by checking for leaks to be on the safe side, but this type of plumbing noise is rarely an issue that needs to be fixed.

If you are sensitive to these plumbing noises, you can choose to encase the pipework, wrap insulation around it, enclose it in conduit, or even box it in using drywall. If the noise is not interrupting your sleep and there are no signs of a leak, you can leave it be.

Water Hammer

As you might expect, a water hammer plumbing noise sounds a bit like someone hitting your pipes with a hammer. The loud banging noise is usually caused by water slamming against a valve and pipes when a faucet is turned off suddenly.

This kind of plumbing noise can be pretty terrifying if you hear it during the dead of night, and it tends to be one of the problems that people are most keen to fix immediately.

Is Water Hammer Harmful?

There’s good reason to get this problem fixed quickly, too. Apart from the noisy plumbing it creates, water hammer can be hard on your pipes, causing leaks over time. It can also cause excessive wear and tear on your washing machine, water heater, or other appliances.

How To Fix Water Hammer

Under normal conditions, plumbing lines have air chambers, which act as shock absorbers for the system.

They allow water to flow into the air space inside the air chamber when a faucet is off, which lets the energy in the flowing water dissipate more gradually, softening the blow and preventing the banging plumbing noise.

If the air chambers have failed, which often happens because the water pressure in the system has forced the water to fill the air chamber, you can do something simple to fix the issue.

First, you need to drain the entire system, so it is emptied of water. Then, turn off the main water supply valve for your house and open all the faucets in your home, allowing all the water to drain out of your system.

Once the water stops running out of your faucets, the system has fully drained. Close the taps and then open the main water valve again. This process should introduce air back into the system and prevent future water hammer plumbing noises.

If that doesn’t work, you’ll need to call a plumber who can diagnose the issue further and might install water hammer arrestors. These devices are cut into the water lines and hold an air charge, which is separated from the water by a rubber diaphragm or piston.

They won’t fill up with water, as a standard air chamber can, and allow the energy in the water to dissipate against the air charge, which happens quietly, eliminating the hammering noise.

Vibrating, Humming, or Whining Noises

Some common reasons for vibrating, humming, or whining noises coming from your pipework when a faucet is on include:

• The isolation valve under the sink is not in a fully open position
• The isolation valve is faulty
• There is too much pressure in the system

The first thing to fix vibrating or humming plumbing noises is to open the isolation valve under the sink fully if it’s not fully open. Often, this is the cause of the issue and is a straightforward fix.

If the valve is faulty, you’ll need to replace it with a new one. This is a simple DIY project, so it won’t cost much to correct.

Check out this great video that walks you through the steps to replacing a valve under a sink.

If replacing the valve doesn’t solve the problem, there’s a possibility that you have too much pressure in your system. You can fix this by installing a pressure-reducing valve, which can be purchased from your local DIY store.

These devices are sometimes called water pressure regulators, and we’ve written an article summarizing the benefits of installing one, which you might want to check out. 

Given that too much pressure is seldom the cause of humming or whining in your pipes, it’s worth calling a plumber to look over your system with a trained eye in case you’re missing something.

The pressure-reducing valve will need to be installed further down the system at the pressure tank or toward the actual main.

Rattling Noises

Rattling plumbing noises from your pipework, especially when you turn a faucet on or off, can be caused by unsecured pipes.

The pipes move when the water flows through them, knocking against a wall or another part of the building, which makes a rattling noise.

Sometimes the clips that hold the pipe in place can shake loose over time thanks to the pressure of the water and the house shifting slightly as it heats up and cools down throughout each day and as seasons change.

Occasionally, the pipes have not been properly secured during construction. If that’s the case and your house was built recently, you might be able to request that the construction company comes back and fixes things for you.

Can a Rattling Pipe Cause Damage?

It is essential to repair a rattling pipe because it will move around a lot, put stress on the joints, and increase the likelihood of springing a leak. So, get this issue fixed before leaks can happen because water damage can be costly to repair.

How To Fix a Rattling Pipe

If the pipe in question is accessible, through an access panel, under the sink, or if it runs along the ceiling in the basement, the job of fixing the rattling plumbing noise is easier.

You can try tightening or replacing loose clips and adding additional fasteners to hold the pipe more firmly in place and prevent it from banging against the wall or other parts of the house.

However, if the pipe is hidden behind a wall, you’re faced with either drilling a hole next to the piece and firing expanding foam into the hole, hoping it will hold the pipe in place more firmly, or ripping a hole in your drywall to get at it and fix it securely in place with clips.

The foam option is probably worth trying first because it is minimally invasive, and if it doesn’t work, all you’ve lost is a can of foam, and the small hole in the wall is quickly covered.

Ripping out drywall to chase down a rattling pipe is a more involved venture, and we recommend calling a plumber to look at the issue before taking such drastic action.

Whistling Or Squealing Noises

Whistling or squealing coming from your plumbing is almost always caused by a worn washer.

These tiny rubber pieces perform the critical job of forming a watertight seal where the valve stem meets the valve seat, preventing water from leaking out of the faucet when it is off.

If the washer is worn, the seal will not be perfect and will allow water to escape around it. This leakage causes high-frequency vibrations due to the turbulence of the water as it passes through the small gaps, in turn making a whistling or squealing noise.

To fix this problem, simply replace the washer with a new one. In some cases, you might need to replace the whole faucet, but try replacing the washer first because that’s much cheaper.

Rubbing Or Ticking Noises

This kind of plumbing noise falls into the category of “expansion noises.”

When your heating comes on or someone turns on the hot faucet, the boiler begins to pump hot water around the system. This hot water causes the metal pipes to heat up, expanding as they do.

They don’t just expand in diameter, either. For example, a 50 ft length of pipe, when heated from 65°F to 200°F, can grow by three-quarters of an inch.

As the pipe expands, it rubs against any walls or floors it is in contact with and shifts against supporting clips, causing the ticking, creaking, or rubbing noises.

As a child, I remember this noise well, but I had no idea what was causing it at the time. It didn’t bother me at all, and I actually found it soothing because I associated it with the heating coming on and warming the house up. Your experience may differ, however.

You can easily fix this issue by replacing clips that allow the pipework to rub against the fabric of the building with clips that hold the pipe away from walls, floors, and other parts of the house using an isolating sleeve.

Look out for “Mickey” clips, named for their striking resemblance to the cartoon mouse.

These clips are made of polypropylene and have a ribbed inner surface to allow expansion and contraction. They are perfect for supporting pipes below joists to eliminate expansion noises.

Metallic Clinking Noises

This is another noise I remember from childhood, and it is caused by mineral salt buildup in the pipes. At the time, we lived in a hard water area where minerals would precipitate out of the water and form a buildup of solid particles in the pipework.

The noise sounded like tiny pieces of gravel flowing through the pipes and making a gentle clinking sound against the wall of the copper pipes.

A solution to this problem is a chemical inhibitor that can be added to the water in the pipes, preventing the precipitation of minerals that cause the plumbing noise.

Summary

Hearing water running through your pipes is not usually a reason to call an emergency plumber, but you must fix some of these plumbing noises promptly before they cause more significant problems.

Water hammer is vital to fix reasonably quickly because it can be hard on your pipework and lead to leaks, as well as being hard on appliances like dishwashers and washing machines. Nobody wants the expense of repairing water damage from a leak or replacing a high-priced appliance.

The same goes for rattling pipes, which put unnecessary stress on joints in the pipework and can be another cause of leaks.

Some plumbing noises are more of a nuisance than an indication of potential damage to your plumbing system. Expansion noises fall into this category.

However, it would be best if you investigated most plumbing noises to find the cause before they grow into an expensive repair. If in doubt, call a plumber and get their advice.

As they say, “A stitch in time saves nine.”