How To Stop Sump Pump Banging Noise (Guide)

The best way to stop sump pump banging noise is to install a quiet check valve. These are specially designed to prevent the banging noise made when it shuts off. First though, it’s worth checking your sump pump over to ensure nothing is worn out or broken.

How To Stop Sump Pump Banging Noise

In this article, I’ll look at the common causes of sump pump banging noises and how best to diagnose any problems. Then I’ll go through the steps of how to stop these irritating noises for good.

Also read: How To Soundproof A Noisy Water Pump In A Few Simple Steps

Why Does A Sump Pump Make Banging Noises?

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A sump pump is designed to remove water from areas below the water table. This is usually in the basement, but it obviously depends on the location and height of your home.

The loud banging noise you hear when the sump pump turns on or off is caused by the check valve. While the noise can be irritating, the check valve performs a very important function.

Its job is to prevent the water being pumped out from flowing back into the pump. In short, it ensures the water only travels in one direction.

This is particularly important when pumping water uphill, as it prevents gravity from interfering.

When the sump pump activates it begins removing water from your home. The water flowing through the pump opens the check valve, allowing it to continue flowing.

But then when the pump turns off, the flow of water effectively reverses. This in turn shuts the check valve, preventing it from flowing back into the pump.

The loud banging noise is caused by the sudden change in pressure inside the pump and its hoses. Banging noises can also be caused by air trapped in the system during use.

This issue is often made worse by the fact that discharge pipes are often poorly secured to joists, and so the change in pressure becomes amplified through vibrations.

In fact, this might be a bigger issue in your home, so is definitely worth checking out. Banging noises from the sump pump can easily travel through your home’s frame and floor, meaning you’ll hear them quite clearly throughout the building.

The check valve is the most common cause of banging noises coming from your sump pump. Luckily this problem is fairly easy to solve and only takes a minor amount of DIY work.

But before you break out the tools and start ordering parts, it’s worth running through a diagnosis of the other common causes of sump pump noise. After all, the last thing you want to do is fix something that’s not even a problem.

Sump Pump Noise Troubleshooting

Is it normal for a sump pump to be loud? A sump pump will always make a level of noise because it’s performing quite a lot of work. Don’t expect to be able to completely soundproof it, but you can reduce its noise considerably.

Before changing the check valve, run through some of the most common causes of sump pump noise.

Vibrating discharge pipe

One of the most common noise sources is a vibrating discharge pipe. As the water is pumped out it causes the pipe to vibrate.

When this pipe isn’t secured properly you’ll be able to hear rattling throughout the house. This is fairly easy to fix and will be covered in more detail in this article.

Poorly maintained unit

A poorly maintained sump pump will have a range of issues caused by things such as a lack of lubrication and cleaning.

Ensure you have your pump regularly maintained by a professional once a year or so. You’ll also find you might need to completely replace the system once every 20 years depending on how well it’s maintained.

The pump is outside the sump pit

A properly installed sump pump should be found inside the sump pit. This contains much of the pump’s noise and is one of the easiest ways to keep it quiet.

If your pump is outside the pit then the noise can reverberate off the basement walls, causing it to sound much louder than it is.

Banging and gurgling coming from the pit

A sump pit should have a good cover over it to block out much of the noise. If not, you’ll quite easily hear all the gurgling and banging noises you otherwise shouldn’t. And, as mentioned, these can easily echo around an empty basement.

Poorly planned discharge lines

Discharge pipes should follow the straightest line possible, as water moving at angles can create a lot of noise. Avoid 90-degree angles whenever possible in favor of 2 45-degree angles instead.

Slurping noises coming from the pump

Another common complaint with sump pumps is slurping noises coming from the pump while it’s turned on. This is usually caused by the pump’s automatic turn-off switch being set to too high a level.

As a result it doesn’t turn off when the water has been removed. Simply adjust the level to solve this problem.

It’s completely normal for your sump pump to make some noise. After all, it’s running a motor to pump water. Banging and gurgling noises are completely normal but can be masked with the right solutions.

Just be sure you’re not covering up something that signals a bigger fault. If you check everything over and it seems fine, then go ahead. But if you’re unsure, contact a professional to check things over before you go any further.

How To Stop Sump Pump Banging Noise

How To Stop Sump Pump Banging Noise

Solving the problem of banging noises from a sump pump is fairly easy and requires minimal work.

The first step is to buy yourself a silent check valve. These aren’t expensive and are easily available. Just be sure to buy one the same size as your discharge pipe. If not, you’ll have to modify the pipe to accommodate it.

Follow these steps to change your check valve.

  1. Locate your shut off valve above the check valve. This will usually be a red handle and prevents water from escaping the pipe.
  2. Use a small wrench to remove the metal bands holding the check valve in place. These are likely very tight.
  3. Expect a bit of water to escape as you remove the old check valve from the pipe.
  4. If you need to modify the discharge pipe to fit the new check valve, do so now. Cut it to size so the new valve fits snugly.
  5. Insert the silent check valve and replace the metal bands, ensuring they’re as tight as possible.
  6. Turn the shut-off valve back on, and you should be good to go.

Consider the following tips too:

  1. If you can, install the new valve at a 45-degree angle. This means modifying the discharge pipe, but will reduce the level of water pressure when the check valve shuts.
  2. Apply some sound dampening materials to places where the discharge pipe comes into contact with your home’s structure. The best choices are soundproofing foam mats or fiberglass pipe wrap.
  3. If possible, remount the discharge pipe using rubber grommets to decouple the pipes from your home’s structure.

Also consider building a new lid for your sump pit. Using some sound dampening materials will help to drastically reduce the amount of noise that escapes the pit.

Again, you’ll want to line the lid with fiberglass insulation or dense acoustic foam, and ensure it’s got a very tight fit around the pit opening.

How Do Silent Check Valves Work?

As mentioned, the common cause of banging noises from a sump pump is the sudden change in pressure when the pump turns off. This is such a common problem that someone invented silent check valves.

While designs will vary between manufacturers, they’ll all follow the same basic idea.

Many have spring-loaded valves or flappers, which make the valve’s closing a bit smoother. Think of soft-close toilet seats and you’re not far off.

This simple yet effective change is enough to reduce banging noises because it basically dampens the closing mechanism and means there’s not such a sudden shift in pressure.

You might still notice a very minor noise while the valve shuts, but it’ll probably be more of a sucking noise than a banging noise. Either way it’s a vast improvement on those loud banging noises you usually hear.

Some Final Thoughts

Fixing sump pump banging noises is generally pretty easy. Providing you’ve got the tools to replace the check valve, it shouldn’t take you longer than 20 minutes. This simple solution is enough to prevent those annoying noises.

That said, be sure to perform checks of your sump pump first so you’re not just covering up a bigger issue. If in doubt, call in a professional to check things over. In the end you might be better off just replacing an old system.

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