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Pool Pump Making Loud Humming Noise [7 Possible Causes]

Silent Home Hub Pool Pump Making Loud Humming Noise

Swimming in your pool can be very relaxing. Just imagine closing your eyes and floating away in your pool. That sounds like a dream that can soon be your reality.

But what ARE WE TO DO with that annoying and LOUD humming noise?

Don’t you wish you could get down to the causes of WHY is your pool pump making loud humming noise? Today, we’ll get to the bottom of that and how to fix it.

Table of Contents

Pool Pump Making Loud Humming Noise: Why It Happens and How to Solve it

Nearly every pool owner has been in this position before. At some point, they’ve turned to the internet and typed in a fix for “pool pump making loud humming noise.”

There are different ways and reasons why your pool pump could be making that annoying loud humming noise. We’ve listed down some of them to help you have a better swimming experience at home.

1. Bent Pump Shaft

To start, a pool pump making a loud humming noise could be because of a bent pool pump shaft near the shaft center.

At some point in its entire operations, the motor’s shaft of your pool pump gets bent and is the SOURCE of why there are noticeable vibrations in the pool pump.

Sometimes the vibrations and noise on the shaft aren’t that apparent, even if there’s already a bent.

The vibrations are hardly noticeable if the bend is closer to the coupling. It only becomes more apparent if the bend is close to the shaft center.

Luckily, DIAL INDICATORS are great at identifying whether a bent pump shaft causes the noise. The process is pretty easy, and you’re set for taking the next step.

But of course, ALWAYS protect your shaft, no matter what the dial indicators say!

2. Internal Blockage

A pool pump making a loud humming noise isn’t necessarily caused by a drastic reason. Often, the noise could be because of a simple internal blockage on the skimmers of your pool pump.

That grinding you hear when you’re under the water? That’s not normal. It’s a good tell-tale sign that there’s probably already A LOT OF DEBRIS that needs to be removed.

Throughout the operation of your pool pump, debris eventually gets sucked into the pump, which is relatively natural. What’s unnatural is if your pool pump accumulated a ton of debris, and yet you don’t clean it.

Clean Your Pump!

If you allow the debris to build up and keep it in poor running conditions, it can cause many problems to your pump impeller and pump motor.

And we’re sure this is something you don’t want to happen anymore.

In case this happens, you need to CLEAN YOUR POOL PUMP:

  • You can fix this by turning off your pump before opening the gasket.
  • After, open the gasket on your pump and take the debris out before getting stuck on the impeller.

This is one of the easy ways to solve the issue yourself, and the results are almost instant, even in poor running conditions.

Cleaning your pump will also reduce the chances of contracting recreational water illnesses!

3. Cavitation

Cavitation usually starts as a simple problem. Unnoticed, it can cause so many problems to your pool pump motor, more than your usual pump noise.

But What is Cavitation?

It takes place when your pool pump doesn’t get enough water even as the pump impeller spins. This produces A LOT OF VIBRATIONS and a very loud humming noise.

More importantly, when your impeller keeps running on that condition, you risk your brass insert separating and overheating the impeller.

There’s a ton of reasons why your noisy pump is creating a bothersome humming noise. So you’re probably wondering HOW you’ll be able to distinguish cavitation from the rest.

Admittedly, you wouldn’t be able to spot cavitation on the first instance, and you’ll need a professional to fix your pumps.

Nevertheless, it is distinct and identifiable by its POPPING and TUMBLING ROCK SOUND inside the pumps.

4. Pump Bearing

An essential part of a pool pump is its bearings.

Bearings are crucial in reducing friction and rock sound for the motor shaft spin.

How Does It Lead to That Humming Noise?

Imagine it as a motor that isn’t well-lubricated and causes that annoying sound. Yikes!

The problem with your pump bearing STARTS GRADUALLY, and often it’s a natural part of owning a pool. As several parts of your pump start wearing down, you’ll start hearing some humming noise and vibrations.

This is caused by the frequency of the vibration of your bearing balls. It gets a little more technical than that, and you’ll need to ask for help from your manufacturer to determine the frequency.

It’s very easy to prevent your pump bearings from developing more issues: Lubricating and oiling your bearings, motor windings, and motor shaft spin is a great way to eliminate any problem with your pump motor.

5. Pump Flow Pulsation

Whenever you’re about to power up your pool’s pump, make sure the discharged valve is open.

Keeping the valve closed is when pump flow pulsation occurs, causing a lot of vibrations and humming noise.

You wouldn’t be able to identify this immediately, especially if you’ve only left the discharge valve closed for a few minutes or so.

But, if you’ve left it closed for too long, then that’s when you’ll start noticing it.

Pump flow pulsation occurs if:

  1. There’s a flaw with the piping designs
  2. Poor spring rates
  3. Lack of proper feed, causing a restricted flow
  4. Worn packing or leaking valves

When the packing or piping designs of your pump are already worn out, it’s time to replace it. They may be causing you lower spring rates.

In addition, to prevent pump flow pulsation from happening, you need to use pulsation dampers for your pump, which is a good fix.

6. Pump Impeller Imbalance

At some point, your pool pump impeller starts to vibrate. It begins as an isolated incident, and eventually, your pump impeller has more and more episodes of this vibration.


You have a swimming pool pump impeller imbalance, causing overheating, force imbalance, misalignment, and have a bad bearing.

And when this is the case, there’s a noticeable amount of vibration on the impeller.

Is a Pump Impeller Imbalance Just a Minor Issue?

We hate to break it to you, but this pump imbalance is a lot bigger than that.

A force imbalance can cause way more issues if left unresolved! That said, you need to CHECK YOUR IMPELLER for issues.

7. Shaft Misalignment

Is your noisy pump making vibrations? It’s usually normal and shouldn’t be a cause for concern.

Nevertheless, we want to play on the safe side and advise you to hire a technician in a repair shop near you. Why?

Your pumping system is capable of making all sorts of vibrations. To ordinary people, these vibrations and noises don’t mean anything…or does it?

EXPERTS can tell if there’s something wrong with the pumping system…like your pump shaft.

Technicians are well-versed when identifying and distinguishing different sorts of vibrations. In this case, they’re better off at determining whether your pumps or your shaft are causing excessive vibrations.

This is very crucial, especially when it comes to addressing a problem or damage with the shaft. A shaft problem is A LOT HARDER to identify, and you’ll need someone’s help for this one.

Nevertheless, there are a few tell-tale signs to know if you’ve got a problem with your shaft misalignment before you start looking for possible fixes.

Shaft misalignment signs include:

  • Axial and radial vibrations
  • Breaking of shafts
  • Loose coupling
  • Oil leaks on the bearing seals
  • Overheating or high temperatures on the bearings and casing of the pump

Should You be Concerned of the Loud Humming Noise of Your Pool Pump?

Pool pump making loud humming noise: Should you panic? NO.

There are different ways and reasons why your noisy pool pump is making loud sounds, and sometimes it might not even be because of a problem.

This is especially true if your pool pump is new or other factors:

  • In most cases, pumps emit a loud humming noise on their first use. You’ve got nothing to worry about just yet, or at least until you start noticing the pump noise getting worse.
  • It could also be one of the faults of your pool pump if it’s naturally noisy. You can find multiple pumps that result in the same power and efficiency with LESS NOISE.
  • Finally, you could be using a powerful pool pump compared to the size of your pool. When this is the case, we recommend looking for the right power and size for your pool.
  • The part/s could be defective (e.g., bearings, shaft, etc.) and may be causing oil leaks.

Before you panic when you hear your noisy pool pump making loud humming noise, RE-EVALUATE THE SITUATION first.

However, if you REALLY want the quietest experience, you can try getting quieter pumps instead. You can check out our review on quiet pool pumps if you think getting quieter pumps will be more convenient.


woman riding a unicorn floatie in a swimming pool

If your pool pump is making a loud humming noise, worry no more. We’ve named all possible reasons why your pool pump is making all that loud noise AND the possible fixes for it.

While many of the factors mentioned above could cause the humming, IT ALWAYS HELPS to ask your local pool technician/expert.

Seriously, just their advice alone can take tremendous pressure OFF your back and your pool’s well…erm…pump.

We hope this article could take some pressure off you!


July 12, 2021 – updated article links, removed product links

June 28, 2021 – updated title, fixed article formatting, updated article links, optimized content

About the Author


Andrea has always been bombarded by the hustle and bustle outside her home. Living in the city doesn’t get any quieter. The never ending noise from construction, traffic, and dogs barking on the streets day in and day out drove Andrea to a breaking point.

For 3 years, Andrea committed herself to studying DIY hacks, performing soundproofing experiments, and installing noise-free solutions. Now, she lives a quiet life free of the stress from noisy environments.

She hopes to share this knowledge so that others don’t have to endure the noise reigning in their ears and live a peaceful, stress-free life.