Swim Jet Considerations: How to Choose One for Your Pool or Hot Tub

Last updated: September 2026

A swim jet can turn a small pool or hot tub into a place you can really swim. It generates a steady counter-current, so you swim in place, a bit like a treadmill for swimming, without needing a full-length lap pool. Before you commit, there are some things to get right so it fits your build and performs as expected.

This article focuses on swim jets installed during the initial construction, rather than retrofit options.

What is a swim jet?

A swim jet, also called a counter-current system, is a device that creates a stream of water strong enough to swim against in place. You can get a full swim workout in a compact space, which is ideal if you have a small pool or a large hot tub. If you want more of the background, read can I build a DIY swim spa? and backyard swim spas.

Swim jets are typically split by how they’re powered: electric pump jets and hydraulic jets. Hydraulic jets are high-powered and create a stronger current, which suits experienced swimmers looking for an intense workout. They are considerably more expensive than pump jets, which are generally enough for recreational swimmers who want moderate resistance for a casual swim.

You can see my range of swim jets in the swim jet shop listing.

Choosing the right swim jet for your needs

• Serious or professional swimmers: a high-powered hydraulic swim jet is likely the best choice. It gives a strong current that closely mimics open-water swimming.
• Recreational swimmers: a standard pump-powered swim jet is enough. It costs less and gives enough resistance for a relaxing, low-impact workout.

The jet I sell is aimed at fitness and recreational swimmers with adjustable flow and angle, rather than athletes in competitive training, and it comes with a 4HP single-speed pump (230V). It’s a machine that generates a flow of water for you to swim against.

Benefits of a swim jet

1. Exercise in limited space. A continuous swim without a long lap pool.
2. Improved fitness. Swimming against a current is a good cardio workout that builds endurance, strength and flexibility, with less impact on the joints than running.
3. Possible added appeal. Some realtors feel a swim jet adds to a property’s appeal. There’s no hard evidence, and I’m a hot tub expert, not a realtor, so don’t take my word for it.

Pool and tub compatibility

Not every swim jet works with every pool or hot tub. The material and construction of your pool decide which jets you can install:

• Concrete or block pools: some swim jets are designed to be built into concrete or block walls. The housing is concreted in during the build and the faceplate goes on when the final surface is finished.
• Fibreglass, vinyl and plastic pools: check that the jet is compatible with your surface before you buy. Not every model is suitable.

If you’re building a concrete tub, DIY hot tub construction and building DIY plunge pools cover the walls, and building a DIY exercise pool covers longer swimming pools.

Size considerations

• Length: a swim jet generally needs a pool at least 4m (about 13 to 14ft) long to work well. In a smaller pool the water can bounce off the rear wall, creating an opposing wave that disrupts your swim. That’s why a normal hot tub is too short. See can I use my hot tub as a swimming pool?.
• Depth: make it deep enough that your hands don’t hit the floor as you swim. The nozzle needs to be a set depth below the surface: for my jet, about 250mm (10in), and the pump must be below the waterline.
• Pump position: keep the pump close. A long pipe run from the pump to the jet costs you flow. My control room design guide explains the distance rule of thumb.

Common mistakes

• Trying to use a cluster of hot tub jets as a swim jet. It doesn’t work.
• Making the pool too short, so the current reflects back off the far wall.
• Deciding on a swim jet after the walls are built. It goes in at the construction stage.
• Placing the pump above the waterline or a long way from the jet.
• Choosing on price alone without checking the flow and the pump that comes with it.

Final thoughts

Choosing the right swim jet comes down to your swimming needs, your pool type and your size limits. Once you’ve decided, the installation is much easier if you’ve planned it from the start. I explain the install in how to install a counter-current swim jet, and here’s my video on one:

Planning a swim spa or plunge pool?

My swim spa plans include the swim jet details, plumbing diagrams and a shopping list for a swim spa build. If you want something more custom, the free Tub & Pool Designer Pro software lets you design it, and I can produce the architectural CAD and 3D plumbing design to go with it.

FAQs

How long does a pool need to be for a swim jet?

At least about 4m (13 to 14ft). In shorter pools the current bounces off the back wall and creates waves that disrupt your swim.

Can I use a swim jet in a hot tub?

Most hot tubs are too short to swim against a proper current. A swim jet suits a plunge pool, cocktail pool or swim spa of around 4m or more.

What is the difference between electric and hydraulic swim jets?

Electric (pump) jets use a pump you install with the jet and suit recreational swimmers. Hydraulic jets are stronger and suit serious swimmers, but cost a good deal more.

Can I retrofit a swim jet?

Yes, retrofit units exist, but for a new build I’d design a built-in jet in from the start. It looks better and the housing sits in the wall.

Is a swim jet the same as a strong pool return?

No. A swim jet is engineered to produce a wide, smooth, powerful current. A strong return or a cluster of hot tub jets won’t give you a real swimming experience.

Got a question about your own build? Drop it in the comments below. I read them all.

Cheers,
Andi

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Thanks - Andi

 

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