Key Considerations for Building a DIY Hot Tub in 2026

So, you’re thinking about building a DIY hot tub in 2026? Well, you’ve come to the right place. On my channel and here at buildahottub.com, there’s a huge amount of information about everything you need for building a DIY hot tub. I’ve got parts, designs, video courses, and absolutely everything you need to make your hot tub dream a reality.

In this article, I’m going to highlight some of the key considerations you need to think about before you even start your DIY hot tub project in 2026. These are the decisions that will shape your entire build, so it’s worth getting them right from the start.

Contents

• Size – How Big Should Your Hot Tub Be?
• Location – Where Will You Build It?
• Control Room Position – Why This Matters
• Materials – What Will You Build With?
• Jets – How Many Do You Need?
• Water Features – Keep Them Separate
• Heating – Your Most Important Decision
• Finishing – The Final Touch

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Size – How Big Should Your Hot Tub Be?

The first thing you need to consider is how big your hot tub is going to be. It seems like a simple consideration, but size really is key.

You need to think about a few things:

• How many people do you want to fit in your DIY hot tub?
• How much space have you actually got available in your backyard?
• Can you heat that volume of water effectively?

Size isn’t just about how many people you want in the tub. It’s also important for heating because you’ve got to be able to heat that body of water. If you make it too big, then it can be a real challenge to get up to temperature.

You want to find that happy medium between the space you have available, the number of people that you want to be able to fit in your hot tub, and of course, the heating capacity as well.

Location – Where Will You Build It?

Next consideration is, of course, location. Now, you may be lucky enough to have several potential spots for your DIY hot tub, or there may be only one space that it could possibly fit in your backyard.

Location is important because as well as the tub itself, you’ve also got to think about where your control room is going to be.

Control Room Position – Why This Matters

Ideally, you want the control room to be within 15 to 20 feet of your hot tub. Any further than that, you can actually lose pressure on your jets, and you don’t really want to go down that route.

Here’s another critical tip: You also want to get the hot tub control room below the water line of your tub.

Why does this matter?

There are two types of pumps:

• Centrifugal pumps – generally hot tub pumps
• Self-priming pumps – generally swimming pool pumps

If your control room is above ground, you need a self-priming pump because a hot tub centrifugal pump is unable to suck air. This is a problem. Well, it’s not so much a problem – it’s more of a consideration because self-priming pumps are much more expensive.

You also don’t get the power on a swimming pool pump that you do on a hot tub pump. Hot tub pumps are designed to move large bodies of water quickly, whereas swimming pool pumps are designed to be more efficient and move a large amount of water very slowly through a filter.

The bottom line: Keep your control room below the water line so you can stay on hot tub pumps. Not only because you get more power for your jets, but it also saves you a whole bunch of money because hot tub pumps are a lot cheaper than swimming pool pumps.

Materials – What Will You Build With?

What are you going to use to build your DIY hot tub?

Your options include:

• Block – CMU (concrete masonry units), a type of hollow block. Inexpensive and really easy to work with – a great choice if you’re going to use block.
• Formed and poured concrete walls
• ICF blocks (Insulated Concrete Forms)

These are all valid ways of building a DIY hot tub in 2026, but you want to choose the method that’s best going to meet your skill set.

Jets – How Many Do You Need?

How many jets are you going to have when you’re building your DIY hot tub? It’s a bit different from a plastic shell tub.

Plastic shell tubs are marketed with hundreds of jets and air nozzles. What we’re building is very different. We tend to have a lot fewer jets, but they’re much larger jets.

Here’s the rule of thumb: You want to have a maximum of 16 jets per pump.

So, if you do want to have more than 16 jets (and 16 is plenty for an 8ft x 8ft or a 10ft x 10ft hot tub), you’re going to have to go for a multiple pump system. You can’t just keep adding endless amounts of jets onto your pump.

There’s a maximum amount of flow that comes off the pump and you need a set flow rate per jet to make sure they’re operating correctly. There’s a bit of a calculation to be done there, but the general rule of thumb is maximum of 16 jets per pump.

Water Features – Keep Them Separate

Are you going to have any water features? Waterfalls? That kind of thing?

If you are, keep those separate. I always recommend that you have them on their own system.

Why?

Water features should have:

• Their own suction
• Their own pump

This gives you control over the flow to get that perfect water feature, and you can have it running when you want.

If you have it tied into the spa pack, for example, you’re going to be limited with it turning off because there’s an auto shut-off on all of the jets as standard on all of the spa packs on the market.

Top tip: If you put your water feature independently on a plug (you could even use a smart plug), you can then control your waterfall by Alexa or Siri. You just have a much finer level of control than you do if it’s plugged into a spa pack.

Keep it separate, keep it on its own plumbing away from the spa pack and the jets in your DIY hot tub.

Heating – Your Most Important Decision

Possibly the most important question: How are you going to heat your DIY hot tub?

Your options include:

• Gas
• Electric
• Air source heat pumps
• And lots of other options

I’m not going to run through all the benefits of each here. I’ve got separate videos on this channel that go through all of the different heating options, summarizing the benefits and downsides of each of them.

But you are going to need to decide how you’re going to heat your DIY hot tub in 2026.

One top tip for you: If you are using an external heater (an air source, a gas heater, or even an additional electric heater), you’re going to want to use a dedicated circulation pump. This ensures it doesn’t get in the way and limit the flow onto the jets with your jet system.

Keep it separate. It makes much more sense.

Finishing – The Final Touch

Finally, how are you going to finish your DIY hot tub?

Your options include:

• Painted epoxy pool paint
• Tiles
• Modern cement finishes
• Natural stone

Here’s an important principle: Don’t allow the finish to be part of the structure.

What do I mean by that?

If, for example, you’re going to do a natural-looking stone finish, don’t have that natural-looking stone as part of the physical structure.

The right way to do it:

1. Build it out of block or poured concrete walls
2. Waterproof it
3. Then treat your finishing surface just as that – a finished surface

Even that natural look stone should be treated as a tile so that it’s totally independent from the structure and the waterproofing layer. It’s always much easier to do it that way.

Summary

So there we have it. These are the main considerations for building a DIY hot tub in 2026:

• Size – Find the right balance for capacity, space, and heating
• Location – Think about both the tub and control room placement
• Control room position – Keep it within 15-20ft and below the waterline
• Materials – Choose what matches your skill level
• Jets – Maximum 16 per pump
• Water features – Keep them on a separate system
• Heating – Choose your method and use a dedicated circulation pump for external heaters
• Finishing – Keep the finish independent from the structure

If you need more information on any of these topics, you can find them inside the guides and video courses, all available at buildahottub.com.

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 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