Water in a Hot Tub Air Blower? How to Dry It Out and Stop It Happening Again

Last updated: September 2026

Water in a hot tub air blower is the last thing you want. If you’ve found this page, you’ve probably already seen the result: your breaker, RCD or GFCI has tripped. We all know water and electricity don’t mix, so in this post I’ll explain why water gets into a blower, how to dry it out, and how to stop it happening again.

Step 1: dry out your blower

The first thing to do is dry out the blower. Before you touch anything, switch off and isolate the power to the tub.

1. Take the blower off. On most blowers you can unscrew the front to detach it from the air line.
2. Unplug it from the spa pack. Most blowers plug into the pack with a plug-in cord (on a Balboa pack, it’s an AMP-style connector), so there’s no rewiring.
3. Empty out any water that’s sitting inside it.
4. Leave it somewhere warm and dry for a couple of days. The airing cupboard next to the boiler is a great place.

Drying it out completely often saves the blower, so you don’t have to replace it. It also stops the tripping. No water, no tripping. If it still trips once it’s properly dry and refitted, the motor is probably damaged, and it’s time for a new blower. Don’t keep resetting an RCD or GFCI that’s tripping. It’s there to protect you. My breaker tripping troubleshooting guide covers the other causes, and How to repair a hot tub blower goes into the repair.

Why does water get into the air lines?

If you have a blower, you have two separate sets of pipes going into the tub: air lines and water lines. They meet in the jet bodies, and that’s where air and water mix. That’s what gives a stronger, bubblier jet.

Why does this matter? When the pump and blower stop, the water settles back under gravity. There are no valves inside the jets, so water flows freely back into the air lines. This is normal. Left alone, it rises in the air pipe until it’s level with the water in the tub. It’s up to us to stop it getting any further, into the blower.

There’s more on how the air and water sides fit together in my DIY hot tub plumbing guide and How to install gunite jet bodies.

What happens if you don’t stop it?

• Your supply trips. A wet blower motor leaks current to earth, and the RCD or GFCI does its job.
• The blower fails. Repeated soakings corrode the motor.
• You can drain the tub through the blower. If the blower sits below the waterline with nothing to stop the water, it can keep running out through the blower’s air intake.

The first line of defence: a check valve

The one thing you absolutely must have is a one-way check valve on the blower line. It only lets air travel one way down the pipe, towards the tub. It opens when the blower pushes air through, and closes when the blower stops, which should stop water getting back to the blower. Waterway’s Poly Storm gunite jet instructions say the same: if you use a blower, an air check valve is mandatory.

If you’ve fitted a clear check valve, turn off the pumps and blower and watch. You’ll see the water back up the pipe towards it.

Why check valves leak

• Too much head of water. The deeper the valve sits below the waterline, the more water is pressing on it, and the more likely it is to weep. You may need a valve with a stronger spring so it closes fully and seals properly.
• Debris. Over time, small bits of grit can get into the valve and stop it closing properly, which lets water through to the blower.
• Age. Springs and seals wear. If yours is old, replace it.

Use physics, not just parts

If you’ve changed the check valve, and even fitted a stronger one, and water still gets through, it’s time to use physics. Water always finds the lowest point it can reach. It can’t climb above the level of the water in the tub on its own.

Option 1: mount the blower above the waterline

If the blower sits above the waterline of your tub, water simply can’t reach it. When I remodelled my own control room, I moved my blower onto a shelf with the air lines running up above the water line. There’s more in My hot tub control room remodel and Hot tub control room position.

Option 2: a Hartford loop

If you don’t want to, or can’t, move the blower above the waterline, put a Hartford loop in the air line. It can go anywhere along the air line between the tub and the blower.

A Hartford loop is a loop, or upside-down “U”, in the air pipe that takes it up and over the waterline before it drops back down to the blower. Water can’t get over the top of the loop, because gravity won’t let it climb above the tub’s water level. So, just like mounting the blower up high, the loop protects the blower with physics rather than a manufactured part.

A few tips:

• Get the top of the loop comfortably above the waterline, not level with it. Allow for the water level rising when people get in.
• Keep the check valve as well. The loop and the valve back each other up.
• Support the loop so it doesn’t sag over time, and use the same pipe size as the rest of your air line.

What I’d do on a new build

Don’t treat the Hartford loop as a last resort for when a check valve fails. Build both in from the start: a check valve and either a high blower or a Hartford loop. It costs a few fittings and a bit of pipe, and it’s far easier to do before the control room is boxed in. There’s more in my top tip for installing an air blower on your DIY hot tub and the ultimate guide to the hot tub air blower.

Not sure you want a blower at all? Venturi jets draw air in without one. The trade-offs are in Do I need an air blower or can I use venturi?

Common mistakes

• Mounting the blower on the control room floor, below the waterline, with no loop.
• Relying on a check valve alone, then never checking it.
• Powering the blower back up while it’s still wet inside.
• Building the loop, but with its top at or just below the waterline.
• Forgetting the air lines when winterising. Water left in them can freeze. See Winterizing a hot tub.

Parts and plans

Replacement blowers and check valves are available from parts4tubs.co.uk in the UK and parts4tubs.com in the USA. If you’re still planning your build, my DIY hot tub plans include the air and water plumbing layout, and The Ultimate Hot Tub Control Room Guide shows where everything goes.

FAQs

Why is there water in my hot tub blower?

Air and water share the jet bodies, so water runs back into the air lines when the blower stops. If the check valve is leaking or stuck, and the blower is below the waterline with no loop, the water reaches the blower.

Can a wet blower be saved?

Often, yes. Isolate the power, remove and empty it, and let it dry somewhere warm for a couple of days. If it still trips the RCD or GFCI once dry, replace it.

Where should a hot tub blower be mounted?

Ideally above the tub’s waterline. If it has to sit lower, run the air line up in a Hartford loop above the waterline, and fit a check valve.

What is a Hartford loop on a hot tub?

An upside-down “U” in the blower air line that rises above the waterline before dropping to the blower. Water can’t climb over it, so it can’t reach the blower.

Do I still need a check valve if I have a Hartford loop?

Yes. Waterway’s jet instructions make an air check valve mandatory with a blower, and the loop and valve back each other up.

Got water in your blower and something here doesn’t add up? Drop it in the comments below. I read them all.

Cheers,
Andi

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Hi, Andi here. I own Buildahottub.com 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.

Fast forward to 2025, I've helped over 1400+ 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