DIY Hot Tub Shopping List: Everything You Need for an In-Ground Build

Updated September 2026. I’ve rewritten this shopping list around what a DIY in-ground hot tub actually needs today: a spa pack, separate jet and circulation pumps, heat pump, filter, UV, lights, cover and the rest. I’ve also corrected a couple of things I got wrong the first time, like lining the hole with a pond liner.

You’ve probably found this site because you’re keen to build your own hot tub. When I started mine there was an awful lot I wasn’t sure of, and I spent hours working out what I actually needed to buy. Not wanting to blow my own trumpet, but since then I’ve helped more than 1,500 people build theirs, so I’m a lot better informed now.

This post is the shopping list: everything you need for a backyard DIY in-ground hot tub, grouped by stage, with notes on what to look for. If you want the “how”, read How to build a DIY in-ground hot tub. This one’s all about what to buy.

Before you buy anything: get the plan right

When I first wrote this list, I said plumbing “depends on size, numbers of jets etc etc”. That’s still true, and it’s exactly why you shouldn’t buy by guesswork. The number of jets decides the number of pumps. The pump sizes decide the pipe sizes. The layout decides how many tees, elbows and metres of pipe you need. Get the design done first and the shopping list writes itself.

That’s what my DIY hot tub plans are for. Each size comes with CAD drawings, the plumbing layout, a full shopping list and notes, and the video course.

1. Groundwork: tools and hire

You’re going to dig a big hole in your garden so you can eventually fill it with water. You’ll need:

• A micro digger (hire), if it’ll fit through your access. It’s by far the least back-breaking option. I originally said hire a JCB, but most gardens only fit a micro or mini digger.
• An electric breaker if you hit clay or rubble. Mine was the best money I spent on the build.
• A spade, shovel, pick and wheelbarrow, even with a digger.
• Somewhere for the spoil to go: skips or a grab lorry. There’s a lot more of it than you think.
• A plate compactor (hire) for the sub-base.
• Pegs, string line, a long spirit level and ideally a laser level.
• A cement mixer (hire). Much easier than mixing by hand. I’m testament to that!

Before any digging, check for buried services (LinesearchbeforeUdig in the UK, 811 in the USA), and in the USA check whether you need a permit. See Do I need a permit for my hot tub?

2. Base and structure

A correction: the original version of this list said to line the hole with a pond or swimming pool liner and then start on the blocks. Today I’d do what a builder would. That means a compacted sub-base, sand blinding and a proper damp-proof membrane under a reinforced concrete slab, and the waterproofing goes on the inside of the finished shell. It’s all explained step by step in the in-ground build guide.

Item	What it’s for / what to look for
Type 1 (MOT) sub-base	A compacted layer under the slab, typically 100–150mm (4–6in)
Sharp sand and a 1200-gauge DPM	Blinding and damp-proof membrane under the slab
Rigid insulation board (compression-rated)	Under the slab and behind the walls. Cuts heat loss into the ground. See DIY hot tub insulation
Rebar, tie wire and spacers	A grid in the slab plus starter bars for the walls. See the rebar guide
Ready-mix concrete (C25/C30)	For the slab, poured in one go
Blocks or ICF	Hollow concrete blocks (CMU) to core-fill. I’d guess 70–100 for a medium to large tub, and mine took 100. Today I’d use ICF: see the best ICF blocks and TubBlox kits
Cement, building sand, concrete for core-fill	Lots of bags. Order more than you think
Render	A scratch coat and a float coat on block walls for a flat, sound surface
Pool-rated waterproofing membrane	e.g. Ardex S 7 Plus (UK/EU, made for swimming pools) or Laticrete Hydro Ban (USA, approved for in-ground pools and water features)
Pool tiles, adhesive and grout	Swimming-pool grade, not what you’d use in the kitchen. I can’t stress this enough. Mosaics are easiest on curves and seats. See Hot tub tiles and Waterproofing, grout and tile adhesive
Coping stones	Stone or porcelain to finish the top edge

3. Plumbing: the parts list

Plumbing is the tricky bit, but it’s really kitchen plumbing on steroids. Here’s what goes in a typical DIY in-ground tub. The exact quantities come from your layout.

Item	Notes
Rigid PVC pipe, Schedule 40, pressure-rated	Imperial sizes (metric won’t fit US fittings). Typically 2in for water, 1.5in for air, 1in and 2.5in for the gunite jet bodies. Use pipe rated to at least 130psi / 9 bar. See Hot tub pipe: the ultimate guide
Fittings	Tees, 90° and 45° elbows (long sweeps where you can), couplers, reducers and unions at the equipment so you can swap parts
Flexible pipe (a little)	Only for awkward connections. I recommend rigid wherever possible. Available in 2in, 1.5in and 1in rolls
PVC primer and solvent cement	The “glue”. Get the right one for pressure pipe. See How to make the perfect PVC solvent weld joint
Two main drains with anti-entrapment covers	Dual drains for safety. In the USA, drain covers must meet the ANSI/APSP/ICC-16 standard under the Virginia Graeme Baker Act. See Installing a main drain
Skimmer	A swimming pool skimmer is fine and often cheaper. See How to install a skimmer
Hydrostatic relief valve	Goes in the floor before you pour. See Why do I need one?
Gunite jet bodies and jet inserts	One body per jet. See Gunite jet body installation
Return fittings	For the circulation and heating loop
Valves	Ball or gate valves either side of the pumps, filter and heat pump, so you can isolate them for servicing and draining (the “stop cocks” in my original list)
Check valves	Including one on the air line to stop water reaching the blower
Pressure test caps and a gauge	Pressure test every line before it’s buried or concreted in

4. Equipment: the control room

This is where most of the money goes, and where the biggest changes have happened since I first wrote this list. Back then I suggested a single big two-speed pump so you didn’t need a separate circulation one. A dual-speed pump is still common on single-pump builds, but my advice now is a dedicated jet pump plus a separate, small circulation pump for filtering and heating. It’s quieter, cheaper to run and works much better with a heat pump.

Item	What to look for
Spa pack (controller, heater and topside)	The brain. It runs the pumps, blower, lights and heater. Make sure it has enough outputs for your pumps. See Configuring a Balboa spa pack and Which topside do I need?
WiFi module (optional)	Control the tub from your phone, e.g. Balboa ControlMySpa
Jet pump(s)	Centrifugal hot tub pumps, mounted below the waterline. As a rule of thumb, one pump per 15–16 jets. See How many pumps do you need? and How to size a hot tub pump
Circulation pump	Small and quiet, and it runs for long periods for filtering and heating. See How to add a circulation pump
Filter	For a hot tub, a cartridge filter is the best option: cheaper and easy to maintain. Buy a spare cartridge. See Cartridge or sand?
Air source heat pump	The spa pack heater gets you up to temperature, and a heat pump keeps it there far more cheaply. See The guide to air source heat pumps for hot tubs and How to control a heat pump with any spa pack
UV-C steriliser	Inline on the circulation loop. I’d choose UV over ozone. See Why you don’t need ozone
Air blower	For bubbles. Block and concrete builds with gunite air lines need a blower rather than venturi. Don’t bother with a heated one, as it isn’t worth it. See Blower or venturi?
Lights	Slim LED lights made for DIY builds, e.g. the super slim 6W spot light (also in 4-packs). See Underwater hot tub lighting made simple

Leave room in the control room. Mine was too small and I’ve had to rebuild it since. There’s more in Hot tub control room design considerations, and my Ultimate hot tub control room guide walks through the layout.

5. Electrics

This is one part where you shouldn’t shop on your own. Your electrician will specify the cable and protection, but budget for:

• A dedicated supply from the consumer unit or main panel, sized for your spa pack and heat pump
• RCD protection in the UK (an RCBO is neatest) or GFCI protection in the USA
• Outdoor-rated cable (usually SWA armoured cable in the UK) and a local isolator or disconnect in sight of the tub
• In the USA, equipotential bonding. See What is ground bonding?

In the UK, a new hot tub circuit is notifiable under Part P, and in the USA it must meet NEC Article 680. There’s more in A guide to hot tub electrics.

6. Cover, steps and chemicals

A good cover will save you money on your bills in the long run. Don’t go cheap. Get a properly insulated, well-fitting cover and a cover lifter so it actually gets used. See the ultimate guide to hot tub covers. You’ll also want steps and a grab rail if they aren’t built in.

Starter chemicals and testing:

• A good test kit or test strips
• Sanitiser: chlorine or bromine
• pH increaser and pH decreaser
• Total alkalinity increaser
• Calcium hardness increaser (if your water is soft)
• Non-chlorine shock
• Filter cartridge cleaner

I’ve dropped the ozone products from my original list, as I’d now use UV-C instead. For how to use all of the above, see The ultimate guide to balancing chemicals in your hot tub.

Want a shortcut? Complete kits

If you’re building a stock tank or cedar hot tub rather than a full in-ground tub, you don’t need to pull together the plumbing and equipment list yourself. My complete kits include the heating, filtration and (if you want them) jets. You just add the tub and the pipe:

• Stock tank kits: heating and filtration only, 4 jets, 8 jets or 16 jets. There’s more on the build in How to build the ultimate DIY stock tank hot tub.
• Cedar and wooden tub kits: heating and filtration only, 4 jets, 8 jets or 16 jets. See How to build the ultimate DIY wooden hot tub.

Where to buy the parts

Blocks, cement, sand and concrete come from your local builders’ merchant or hardware store. For the hot tub parts (spa packs, pumps, heat pumps, filters, jets, lights, plumbing fittings and chemicals), I set up parts4tubs.co.uk in the UK and parts4tubs.com in the USA for exactly this reason.

Common shopping mistakes

• Buying before the design is finished, especially pumps and pipe.
• Mixing metric and imperial pipe and fittings. They don’t fit together.
• Non-pressure-rated or thin-wall pipe on a pressurised system.
• Kitchen tile adhesive and grout instead of pool-grade.
• A single drain with a flat cover instead of dual drains with anti-entrapment covers.
• A pump sat above the waterline, which leads to air locks and priming problems.
• Skimping on the cover, which you’ll pay for in heating bills.
• A control room that’s too small for the kit you end up with.

Want it drawn up for you?

The easiest way to get an accurate shopping list is to start from a design. My hot tub plans include one for every size, and there are also infinity hot tub plans and swim spa plans. If you want something truly custom, try the free Tub & Pool Designer Pro software, and I can turn your design into architectural CAD and a 3D plumbing design.

FAQs

What do I need to build my own hot tub?

For an in-ground tub: groundwork tools and hire, concrete and rebar for the slab, block or ICF walls, render, waterproofing and tiles, then the plumbing (pipe, fittings, drains, skimmer, jets, valves), the equipment (spa pack, pumps, filter, heat pump, UV, lights, blower), the electrics, and a cover.

How many blocks do I need for a DIY hot tub?

It depends on the size and wall height. As a rough guide, 70–100 blocks for a medium to large tub. Mine took 100. Your plans will give you the exact number.

What size pipe does a DIY hot tub use?

Rigid Schedule 40 PVC in imperial sizes: typically 2in for the water lines, 1.5in for air, and 1in and 2.5in for the gunite jet bodies. It should be rated to at least 130psi (9 bar).

Do I need a separate circulation pump?

It isn’t essential, as a dual-speed pump can do both jobs, but I’d recommend one. A small circulation pump for filtering and heating is quieter, cheaper to run and pairs well with an air source heat pump.

Can I buy a kit instead?

Yes. For stock tank and cedar tubs, my complete kits include heating, filtration and jets. For an in-ground build, the plans give you the full parts list to buy from.

Anything you think I’ve missed from the list? Let me know 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