In-Ground Hot Tub Designs: Shapes, Levels, Surrounds and Lighting

Last updated: September 2026

What makes a good in-ground hot tub design? Few things are as relaxing as a soak in a hot tub, but when it comes to creating a garden or backyard you love, the way the tub sits in the space makes all the difference. A freestanding tub can be functional and convenient. A well-designed in-ground tub looks like it was always meant to be there.

This post is about the design of the space around the water: the shape, how high the tub sits, the coping and surrounds, the steps, the lighting, and how it all ties into your garden. If you’re after seat heights, water depths and jet layouts, those are covered in What makes a good DIY hot tub design?, so I won’t repeat them here.

One thing I won’t cover is dropping a plastic shell hot tub into a hole. It rarely works well, because shells are designed to sit above ground, with access to the equipment all round. For a true in-ground hot tub, you want to build one. Don’t worry: with my help, it’s easier than you think.

What is an in-ground hot tub?

An in-ground hot tub is built into the ground rather than sitting on top of it. Instead of a freestanding cabinet, the tub is part of the landscape, level with (or rising just above) the patio, deck or lawn around it. It’s usually built from concrete block, poured concrete or ICF (insulated concrete form) blocks, waterproofed and then finished with tiles, render or stone.

Because you’re building it, you can make it any size or shape, and it can sit alongside other features like a pool, a patio or a fire pit. That freedom is the whole point, but it also means the design decisions are yours. For the build itself, see the DIY in-ground hot tub build guide and In-ground hot tubs: a DIYer’s guide.

Shape: simple usually wins

Shape	Looks	Build and running
Square or rectangle	Clean and modern. Sits neatly against a patio, deck or wall	The easiest to build, tile and cover. My first choice for most DIY builds
Round	Sociable, with everyone facing the middle	Curved walls need poured concrete, ICF or careful blockwork, and small mosaic tiles
Octagon	A round feel with straight walls	A good compromise. See Octagon hot tub
L-shape or freeform	Natural, lagoon-style, or wrapped around a corner	The hardest to build, cover and plumb evenly. Custom cover required

Whatever the shape, remember the cover. A square or rectangular cover is standard, while anything else is made to measure and costs more. See The ultimate guide to hot tub covers.

Levels: flush, semi-sunken or raised?

“In-ground” doesn’t have to mean the rim is at ground level. How high the tub sits is one of the biggest design decisions you’ll make.

• Flush (fully sunken): the coping is level with the patio or lawn. It looks sleek and gives the best views across the garden, but it’s the biggest dig, and it’s a trip and fall hazard for children and pets, so a lockable cover is a must. Getting in and out means steps inside the tub.
• Semi-sunken: the tub is partly dug in, with the edge raised to around seat height, about 45cm (18in). It suits a lot of gardens. You can sit on the edge and swing your legs in, the raised wall makes a natural barrier and gives some privacy, and there’s less digging. The raised section needs finishing, whether that’s render, cladding, stone or tiles.
• Raised (above ground): no big dig, the easiest access to the plumbing and a good fit for a high water table or rock. The walls have nothing behind them, though, so they must be designed to take the water pressure and need insulating. See Above ground hot tubs.

On a sloping garden you can use the slope: sunk into the high side and raised on the low side. That’s also a great setup for an infinity or overflow edge facing the view.

Coping and surrounds: tying it into the garden

The coping (the edging around the top of the walls) and the surface around the tub do more than anything else to make an in-ground hot tub look finished.

• Coping: natural stone, porcelain or precast pool coping, usually with a rounded (bullnose) front edge that’s comfortable to lean on. It should overhang the inside wall slightly. Use frost-resistant, non-slip material.
• Surrounds: paving, porcelain, stone or composite and timber decking are the usual choices. Keep the finish non-slip when wet, and make it drain away from the tub, not into it. Wet feet and smooth surfaces don’t mix.
• Decking: if a deck goes around the tub, the tub should sit on its own foundations, with the deck built around it. Leave a hatch or removable panel for access to anything underneath. See Hot tub deck ideas.
• Match the house. Using the same stone or colour as your patio, walls or window frames makes the tub look like it was always there.

Inside the tub, the tile choice sets the mood. Dark tiles look deep and dramatic. Light blues and whites look clean and fresh. I’d use small mosaic tiles over large tiles every time, because they follow the seats and curves far better. See Hot tub tiles and Waterproofing, grout and tile adhesive.

Steps and getting in

With a flush tub, your steps are inside it, and they take up seating space and water. With a raised or semi-sunken tub, you may want steps outside too. Either way:

• Keep treads deep and risers even, with a non-slip finish.
• Mark the step edges with a contrasting tile or a light, so people can see them at night.
• Add a handrail if anyone older or less steady will use it.
• A wide corner step can double up as a seat for children or a cool-down perch.

There’s much more in Hot tub steps: the ultimate guide.

Lighting and ambience

Lighting is where an in-ground tub really comes alive at night.

• In the tub: LED lights on a low-voltage supply, with the power supply kept in the dry control room. In the UK, lights in the water should be SELV (12V AC or 30V DC maximum). Plan the cable sleeves before you render. See The ultimate guide to hot tub lights. My Super Slim hot tub and pool light and 6W spot lights are designed for DIY builds.
• Around the tub: soft, low-level lighting on steps, paths and planting, rather than bright floodlights that attract insects and dazzle you.
• Water features: a waterfall or stainless water blade adds sound and movement, but it needs its own pump and suction. See Adding a water feature and Water blade installation tips.
• Fire: a fire pit alongside is a lovely combination, as Francisco’s fire pit hot tub build shows. Keep it a safe distance from covers and timber.

Location, views, privacy and shelter

• The view from the water. Sit on a garden chair where the tub will go, at the height your head will be, and look around. Face the tub towards the best view, the sunset or the garden, not the neighbour’s bins.
• The view from the house. You’ll look at it every day, even in winter, so make it look good from the kitchen window.
• The walk from the house. Short, well lit and non-slip. You’ll be doing it in a dressing gown in January.
• Privacy. Screens, hedging, trellis and pergolas all work. See Hot tub privacy ideas.
• Shelter. Wind strips heat from the water fast, so a screen on the prevailing wind side helps both comfort and running costs. A pergola or canopy gives shade in summer and keeps the rain off in winter.
• Trees. Leaves, blossom and pine needles end up in the water and the skimmer, and roots don’t mix with buried pipework.
• Services and drainage. Check for buried services before you dig, and think about where the water goes when you drain the tub.

Hiding the control room (without hiding it too well)

An in-ground tub needs a control room for the pumps, filter, spa pack and heater. It should be close to the tub, ideally below the water line, and much bigger than you think. That’s the part I got wrong on my own build. The design trick is to make it disappear: under a deck, behind a planted screen, inside a garden store, or built into a retaining wall on a sloping garden. Just keep a proper door and enough room to change the filter without a fight. See Hot tub control room design considerations.

If you’re using an air source heat pump, give it a spot with airflow that’s not right next to where you sit. They make some noise. See How noisy is an air source heat pump?

Combining it with a pool or plunge pool

Many of the most striking in-ground designs pair a hot tub with a pool or a cold plunge, often with the hot tub spilling over into the pool. It looks fantastic, but plan the plumbing carefully: in most cases the hot tub and pool should run as separate systems. See Hot tub pool combo, Adding a spill-over hot tub and Why pool and hot tub plumbing should remain separate.

Safety features to design in

• A lockable safety cover, especially on a flush tub. In the USA, many areas also require a barrier around a spa. See Do I need a permit for my hot tub?
• Two main drains with anti-entrapment covers. In the USA, drain covers on public pools and spas must meet the standard set under the Virginia Graeme Baker Act. It’s good practice at home too.
• Non-slip surfaces on the steps, coping and surround.
• Temperature: no more than 40°C (104°F).
• Electrics: a dedicated RCD- or GFCI-protected circuit, with an isolator or disconnect within sight of the tub but out of reach from it, fitted by a qualified electrician. See Hot tub wiring explained.

What does an in-ground hot tub cost?

The cost varies hugely with size, shape, finish, features and how much you do yourself. For a DIY build, I’d budget from around $10,000–15,000 for a well-specified in-ground tub. It can be done for less if you keep it simple, and a stock tank tub is far cheaper again. Get a spa builder involved and it could be $25,000 or more. For comparison, HomeGuide puts custom-built in-ground hot tubs at $8,000–25,000 installed, with extras like waterfalls costing more.

The design choices in this post are what push the price up: curves, infinity edges, stone coping, lighting, decking and water features all add up. Decide which ones really matter to you. Don’t forget the running costs either. Insulation, a good cover and an air source heat pump make the biggest difference. See Hot tub energy efficiency.

Common in-ground design mistakes

• A complicated shape for a first build, then a big bill for a custom cover.
• A flush tub with no lockable cover in a garden used by children.
• Smooth, slippery coping or paving around the water.
• Surrounds that drain into the tub, washing soil and debris in.
• Nowhere to put the cover when it’s off.
• A control room that’s beautifully hidden but impossible to work in.
• Siting it under trees, or in the windiest corner of the garden.
• Adding lights or water features later, when the sleeves and pipework needed to be in before the render.

Want your design drawn up?

This is where I can really help. If a standard layout suits your garden, my DIY hot tub plans give you CAD drawings with every dimension, the plumbing layout, a full parts list and the video course. There are infinity hot tub plans if you have a view to show off.

For a custom in-ground design, sketch your idea in the free Tub & Pool Designer Pro software, and I can turn it into architectural CAD and a 3D plumbing design you can build from or use for permits. If you want me to take it from a rough sketch all the way to a 3D model, plumbing, CAD, build guide and parts quotation, that’s my custom hot tub design consultancy, or the hot tub and pool combo design consultancy if there’s a pool too. I’ve explained how the custom design process works step by step.

FAQs

Can I put a shop-bought hot tub in the ground?

I wouldn’t. Shell tubs are designed to sit above ground, with access to the pumps and pipework all round. Sink one and servicing becomes very difficult. For a true in-ground tub, build one.

What is the best shape for an in-ground hot tub?

For most DIY builds, a square or rectangle. It’s the easiest to build, tile and cover. Round, octagonal and freeform shapes look great but cost more to build and need a made-to-measure cover.

Should an in-ground hot tub be flush with the ground?

It doesn’t have to be. A semi-sunken tub with the edge at about seat height (45cm / 18in) is easier to get in and out of, safer for children and pets, and needs less digging.

What is the standard size of an in-ground hot tub?

There isn’t one, because they’re custom. The most common DIY size I see is 8ft x 8ft (about 2.4m x 2.4m) internally, with around 90cm–1m (36–40in) of water.

How long does an in-ground hot tub take to heat?

It depends on the volume and the heater. As a rule of thumb, every 1kW adds about 0.86°C per hour to 1,000 litres, before losses, so a 3kW element on a 2,800-litre tub manages under 1°C an hour. A large heat pump or gas heater is much faster. See What is the best method to heat my DIY hot tub?

What do I do with a broken in-ground hot tub?

Most problems are in the equipment or plumbing, not the structure, so it can usually be repaired. See Restoring or repairing a hot tub and How to detect and fix a hot tub leak. If you no longer want it, it can be filled in or turned into a planter or pond, but disconnect the electrics safely first.

Designing an in-ground tub? Share your ideas or questions 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