Noisy Hot Tub Pump?

Noisy Hot Tub Pump

In this article, I am going to talk about how to fix a noisy hot tub pump. This article was inspired by a friend of mine Paul who I helped today fix his own noisy hot tub pump. Whilst I don’t do on site work, I can never say no to a friend with a hot tub in need 🙂

There are a number of potential causes of a noisy pump so let’s explore what they are and how you can fix them.


What type of noise is your hot tub pump making?

The first thing to do with a noisy hot tub pump is try and diagnose the type of noise that it is making.

If you hear a humming noise and not a lot else, read the next section that explains what this could be.

If you hear a “knocking” sound then there could be some damage to the impeller on the pump so you will need to inspect it and probably replace it (or the whole pump which is more expensive but much easier to do)

If your pump is making a louder than normal noise in general, you could have something lodged in the impeller. You will need to disconnect the pump from the pipes and see if anything is stock inside the impellor itself.

Any kind of high pitched noise tends to indicate bad bearings so you probably want to be buying a new pump.

Just on a side note, if you pump is tripping your breaker, then you either have water in your pump or have had water in your pump and now your coil has rusted. A couple of days in a warm room next to a radiator will usually dry out the pump. If the coil has rusted, I would replace the pump – way too much hassle to try and repair it and it will only get worse over time and trip the breaker more.

What is or is not happening?

What do I mean here? Well, if the hot tub pump is humming for example but there is no water coming out of your jets, then the chances are that the capacitor has blown or gone bad. Without the capacitor, the hot tub pump will not be able to start.

If you hear a humming when you press the jets button but when you look at the pump it is not physically turning, then this is your problem. Kill the power to the tub and carefully remove the cover at the top of the pump.

You can then see what capacitor you have and replace it like for like – a quick, inexpensive and easy fix to make. Burn marks or bulges on the capacitor are a sign that it has failed.

What if there is little to no flow coming out of the jets?

Little to no flow coming out of the jets could in the first instance, be an air lock. If you have recently filled up your hot tub then this is likely to be the culprit. There are a number of ways to remove an air lock but I have a much more detailed post on that here you can read about here.

Likewise, and in the case of my friend Paul, this next one was his problem. If you have checked for an air lock and don’t have one, but you do have decreased flow and a noisy pump then there is a good chance you have something lodged in the impeller.

After ruling the other potential problems out on Paul’s tub, when we finally got into the back cabinet (the access is not great so took a lot longer than it should have to gain access) it didn’t take very long to check this.

Make sure that you lock of both of the gate valves on the pump to isolate it. That way, you can safely undo the union at the front of the pump and inspect the impeller. You will have already turned off the power at the breaker, so you can put your fingers inside of the pump and see if you can find anything wrapped around the impeller.

In Paul’s case, it was the part of the filter that had come loose and then lodged itself around the impeller. This caused it to spin “out of shape” and vibrate which was the noise we could hear and also reduced the flow on the jets too.

We removed the debris and that fixed it straight away. Bingo!

Noisy Hot Tub Pump-2
Noisy Hot Tub Pump-2

Top tip when removing a union nut, if it is too tight, then you can use an oil filter wrench on it. It works like a charm. Sub 10 bucks on Amazon and if you are going to be servicing your tub then you should have one in your garage, they come in very handy!

Difference between and Air Lock and a blockage on the impeller?

This is a tough one because the symptoms are the same. The way that we ruled out an air lock on my friend Paul’s tub was that he dropped the water and refilled. This is always the last resort to remove an air lock but it is very effective.

It is highly unlikely that after a second refill (always through the filter or the highest point in your plumbing) you would have exactly the same kind (and size) of an air lock. In Paul’s case, after the refill the symptoms were exactly the same so this indicated that the problem was something else.

In Conclusion

The first thing that I am going to point out here is that if you can’t get to the problem, you are not going to be able to fix it. What do I mean? Service access for your tub is really important.

Whether you are building your own or buying a plastic shell tub, you need to be able to get at the parts to service them.

Today, Paul and I spent best part of 2 hours trying to access the parts (eg the pump in question) and the “fix” took 5 minutes tops.

Make sure you give yourself plenty of space to get at the internal parts of your hot tub. Before you integrate the hot tub into a deck or against a wall, check you are not going to stop access to any of the mechanical parts – you never know when you need to get at them!

Happy “noise free” Hot Tubbi’

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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