What Makes the Best DIY Hot Tub Plans? What to Look For

Last updated: September 2026

Can you build your own hot tub in the backyard? Yes. I’ve now helped more than 1,500 people do it, and the difference between a build that goes smoothly and a DIY disaster is almost always the plan. You save a lot of money compared with a pro spa builder, and you get the satisfaction of making your own backyard oasis, but only if you know what you’re building before you dig.

Late summer is when the second wave of builds starts, with people racing to finish before the weather turns in the fall (autumn in the UK). Here’s what separates good plans from a sketch on the back of an envelope.

What makes a great set of DIY hot tub plans?

DIY hot tub construction takes some know-how, and even the best plans won’t build themselves. Be honest about your skill level. Good plans work for beginners as well as for experienced builders.

1. Clear step-by-step instructions

Forget winging it. You want detailed, easy-to-follow instructions, a bit like a personal construction coach. Bonus points for troubleshooting tips, because even the most careful builder hits the odd hiccup. If you’re not sure where to begin, start with I want to build a hot tub, where do I start? and 7 DIY hot tub mistakes to avoid.

2. Real dimensions

You can’t order concrete, block or pipe from a picture. The plans should give internal and external dimensions, seat heights, water depth and where every jet, drain and return goes. The build-up from the bottom of the hole to the tiles is covered in my in-ground hot tub build guide.

3. A choice of wall construction

Popular options are poured concrete, concrete block and ICF (insulated concrete forms). Good plans explain the pros and cons of each so you can pick the one that suits you. If laying block gives you a headache, poured concrete or ICF may suit you better. I go through them in hot tub wall construction options, and the best ICF blocks for a hot tub if you’re leaning that way.

4. A full plumbing layout

The plumbing is where most first-timers get nervous, and it’s the part that’s hardest to fix once the concrete is poured. Look for a diagram showing pipe sizes, pump connections, drains and the route back to the control room. My plumbing guides are a good primer: DIY hot tub plumbing and how hot tub plumbing works.

5. A parts and materials list

A comprehensive shopping list means you have what you need before you dive in (literally). It also lets you price the build honestly before you start. See the DIY hot tub shopping list for a general idea of what’s involved.

6. Room to adapt

Budgets and preferences vary, so choose plans that can be modified: a different depth, seating layout or jet count. Ideally the designer will help if a building authority asks for changes.

7. Structural drawings if you need a permit

If your area requires a permit, or you’re using a general contractor, you’ll usually need drawings a building authority will accept. Ask before you buy whether the plans include structural drawings, and check with your local building department. There’s more in do I need a permit for my hot tub?.

Beyond the basics: choosing the right plan

Heating

Electric, gas or propane, and air source heat pump each have their own pros and cons. The plan should leave room for whichever you choose. I compare them in the best method to heat a DIY hot tub.

Control room position

Don’t underestimate this one. Try to put the control room below the water line and as close to the tub as you can, ideally within 15 to 20 feet (about 4.5 to 6m). That keeps the pipe runs short, which keeps the jet pressure up, and it lets standard hot tub pumps prime naturally. My guide to control room design covers it in detail.

Customisation

Size, seating arrangement and jet placement should all suit you. Imagine soaking under the stars in a tub designed for you, rather than for a catalogue. If you have an odd-shaped space, DIY hot tub design has more, and in-ground hot tub designs shows what’s possible.

What’s in my plans?

My DIY hot tub plans are built around all of the above. According to the shop page, you get:

• Professional CAD designs with two plumbing options: a single pump with 14 jets, or a dual pump with 14 jets that works with gas, propane, electric or air source heating.
• Architect-drafted structural blueprints suitable for permit submissions.
• Complete plumbing diagrams, standalone and combined.
• A 130-page installation guide (the 2026 Ultimate DIY Guide).
• A video masterclass of 40+ lessons.
• A parts and materials shopping list with online purchase links.
• Lifetime email support.

They come in imperial (feet and inches) and metric, in sizes from 6ft x 6ft up to 12ft x 11ft, at $149. If you want a raised overflow edge, there are also infinity hot tub plans, and for a swimming machine see the swim spa plans.

Want it drawn up for you?

If your space, shape or ideas don’t fit a standard size, try the free Tub & Pool Designer Pro software to lay out your own design in 3D. I can then turn it into architectural CAD and a 3D plumbing design for a contractor or a permit application.

FAQs

What should DIY hot tub plans include?

At minimum: dimensioned drawings, a plumbing layout, a parts and materials list and clear step-by-step instructions. If you need a permit or a contractor, ask for structural drawings too.

Are DIY hot tub plans worth paying for?

In my experience, yes. Mistakes in the dig, the walls and the plumbing are the expensive ones, and a good plan is much cheaper than rebuilding a wall. It’s also far easier to order materials with a proper parts list.

Which is easiest to build, block, ICF or poured concrete?

Block is widely available and forgiving, ICF is quick and gives you insulation built in, and poured concrete gives a seamless finish but needs strong formwork. The best one is the one that suits your skills and your location.

Can I change the size or shape of a set of plans?

Usually you can, within reason. Check that the plans are adaptable and that the designer will support changes. For fully custom shapes, a custom CAD design is the better route.

Do I need planning permission or a permit?

It depends on where you live. In the UK, a garden hot tub usually doesn’t need planning permission, but the electrics must meet Building Regulations. In the USA, many areas require a permit for an in-ground tub, so check with your local building department.

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