Darren’s DIY Hot Tub and Swim Spa in Arizona (Case Study)

Last updated: September 2026

Darren got in touch with me in April 2024 because, like most of my customers, he’d been quoted an astronomical amount of money to build a hot tub-come-swim spa.

The conversation always goes the same way. “I spoke to several pool builders, and the quotes I got were outrageous,” he began. “I think I can do this myself with your help.” Well, Darren, you’ve come to the right place, I replied.

From there, we had a good chat about the specification and features he was looking for, and then it was time for me to get started on the initial design renders.

The design

As with all my custom design projects, we went back and forth with the design until the customer, Darren in this case, was totally happy. Below is the result, and it’s what Darren is building. You can read how that works in the custom design process, step by step.

Essentially, this is a swim spa with a swim jet, a 14-jet system, and a tanning ledge or Baja shelf. There are also a couple of bubblers built into the Baja shelf. If you’re not familiar with bubblers, they’re popular on swimming pools. They’re basically mini jets that send water upwards to create a bubbling effect.

For these, we’re using some regular pool returns and a medium-sized hot tub jet pump. That gives the result we’re after at a fraction of the cost. Remember, anything with “swimming pool” in the name comes with the dreaded “swimming pool tax”. Basically, it just costs more! There’s more on this in can I use pool parts on a hot tub?

Solar and gas heating

We’ve designed some other features into the plumbing. First, Darren wants to use a circulating solar panel system to add extra heat. To do that, we’re linking it in with a heat exchanger. I’ll cover this in more detail when we get to that point in Darren’s build. In the meantime, see can I heat a hot tub with solar power? and heat exchangers explained.

To make sure he can always get up to temperature in all weathers, there’s a gas heater too. For something this size, an electric heater just isn’t practical. It would be too slow and cost the earth to run. See hot tub gas heaters and what size heater do I need?

With the planning done, I supplied Darren the plumbing diagrams and all the parts, and it was time for him to get to work.

Excavation and the base

The first step was a big hole. You can see in the background of the photo below just how much dirt comes out when you excavate. This wasn’t done by hand!

Next was the base. If you’re using swimming pool-style drains, like Darren is, remember that they have to be set into the rebar structure before the pour, along with their connecting pipes. See installing a main drain and my rebar guide.

The walls

With the base done and cured, it was time for the walls. The photo below shows where things stood at the end of May 2024. Darren is ploughing through this project at a real pace.

This is an ongoing project, so check back for the latest update. In the meantime, if you’re weighing up a build like this, have a read of backyard swim spa: everything you need to know, what does a swim spa cost? and swim jet considerations.

Planning your own swim spa?

My swim spa plans include the drawings, plumbing layout, a parts list and the video course. For the swim jet itself, I sell the counter current swim jet with pump, the dual pump version and the jet without a pump, and how to install a counter current swim jet shows how it goes in. If you want something bespoke like Darren’s, my custom hot tub design consultancy gets you a design and my support through the build.

FAQs

Can you build a hot tub and swim spa in one?

Yes. Darren’s combines a swim jet, a 14-jet hot tub system and a Baja shelf in one body of water, designed together from the start.

What are bubblers on a Baja shelf?

Small upward-facing jets set into a shallow tanning ledge that make the water bubble. Darren’s use regular pool returns fed by a hot tub jet pump.

Is electric heating practical for a swim spa?

Not for one this size. It would be slow and expensive to run, which is why Darren has solar heating through a heat exchanger, with a gas heater to make sure it always gets up to temperature.

Got a question about a swim spa build like Darren’s? 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