Domestic vs Commercial Hot Tubs: The Differences (and Holiday Let Rules)

Last updated: September 2026

Some people are tempted to take a domestic hot tub design and use it commercially: in a hotel, a gym, a glamping site or a holiday let, and start charging for it. I’m afraid I have some bad news. Not every hot tub is built for commercial use, you can’t use just any hot tub in a commercial setting, and you can get into serious trouble with the authorities if you try.

I design hot tubs and plunge pools for domestic use only, and there’s a good reason for that. In this post I’ll explain the main differences between domestic and commercial hot tubs without getting lost in the technical detail, and by the end you’ll see why I stay firmly on the domestic side.

What counts as a commercial hot tub?

It isn’t only the big spa pool at a leisure centre. If a hot tub is used as part of a business, it’s no longer simply domestic. That includes hotels, gyms, spas, holiday parks, glamping sites, Airbnbs and holiday lets, and even hot tubs on display in a showroom.

In the UK, the Health and Safety Executive’s guidance is HSG282, Control of legionella and other infectious agents in spa-pool systems. It covers spa pools in leisure centres, hotels and holiday homes, and it includes specific advice on “domestic-type spa pools or hot tubs used as part of a business activity”, such as holiday-park rental units and hotel bedrooms with a dedicated spa.

In the USA, pools and spas open to the public are regulated by state and local health codes. Many of those are based on the CDC’s Model Aquatic Health Code (MAHC). The MAHC is guidance rather than federal law, so each jurisdiction decides how much of it to adopt. Whether a rental property’s hot tub counts as “public” varies from place to place, so ask your local health department.

Domestic vs commercial hot tubs at a glance

	Domestic (your own garden)	Commercial (UK HSG282 examples)
Design	Skimmer, or an infinity edge by choice	Deck-level overflow with a balance tank sized for the bather load
Turnover	Filter cycles you set in the spa pack	15 minutes maximum for lower bather loads, 6 minutes for commercial-type spas
Bather load	You decide who gets in	Designed for a set load, with at least 250 litres of water per bather
Sanitising	Chlorine or bromine added by you	Inline feeder on domestic-type spas, automated dosing and control where the risk is higher
Water testing	Regularly, by you	At least twice daily (domestic-type), or at opening and every two hours (commercial-type)
Lab testing	None	Monthly microbiological tests and quarterly Legionella tests
Draining	When you choose	Domestic-type: all the water replaced weekly, or after each group of users if sooner
Records	Up to you	Test and maintenance records, with results kept for at least five years

Figures from HSE HSG282. Your risk assessment and local authority decide what applies to you.

The design: overflow and balance tanks

At its core, one of the biggest differences is the design. Commercial hot tubs are typically overflow spas, with a balance tank to store the water displaced by bathers. That’s essential, because you can never predict exactly how many people will be in the tub at once.

Even with a sign saying “maximum 10 bathers”, what happens when 12 people jump in? If the balance tank isn’t big enough, that extra water has to go somewhere, and the last thing you want is water flooding your facility. So the balance tank has to be sized for those swings. HSG282 says it should be sized for the bather load and easy to get into for inspection and cleaning.

A domestic hot tub usually relies on a skimmer (unless it’s an infinity or overflow tub). The water level rises and falls as people get in and out. Because you control how many people use your own hot tub, you can plan for that displacement and let the skimmer cope. As a rough guide, each adult displaces something like 70 litres (about 18 US gallons) of water when they get in. See How to install a skimmer.

Turnover and flow rates

Turnover time is how long it takes for the whole volume of water to pass through the filter. This is where domestic and commercial really part company.

At home, you set filter cycles in the spa pack to suit how you use the tub. In a commercial setting, turnover is set by the expected number of bathers, and you have to prove the plumbing and equipment can achieve it. HSG282 sets a maximum design turnover of 15 minutes for lower bather loads and 6 minutes for commercial-type spa pools. In other words, the entire volume of water has to go through the filter every six minutes.

To do that, commercial hot tubs need much bigger pipes, pumps and filters. Standard domestic equipment simply isn’t built to move that much water. And for the jets and the turnover to work, the flow has to be proved by calculations and then by testing. That leaves little room for error. If a plumber adds a few extra 90° bends during the build, the flow can drop and the spa can fail to comply. Commercial spa design is a balancing act, and it has to be right from the start.

There are safety differences too. In the USA, the Virginia Graeme Baker Pool and Spa Safety Act requires public pools and spas to have anti-entrapment drain covers, and a secondary anti-entrapment system where there’s a single blockable drain. I’d always fit twin drains with proper covers on a domestic build too. See Installing a main drain.

Chemical treatment: domestic vs commercial

In a home hot tub, chemical treatment is about keeping the water safe and clean for your household. You test, add a bit of chlorine when it’s needed, and keep the pH in range. The CDC recommends at least 3ppm free chlorine in a home hot tub and pH between 7.0 and 7.8. My full guide is Hot tub chemical levels.

A commercial hot tub is a different challenge entirely:

• Automatic dosing and control. HSG282 says that where risk factors are higher, such as a high bather load, chemical dosage and control should be automated. For public hot tubs, the CDC’s Legionella guidance for operators recommends automatic feed and control, free chlorine of 3–10ppm (or bromine 4–8ppm), pH of 7.2–7.8, and testing at least twice a day, as often as hourly when busy.
• Logs. Chemical levels are recorded at set intervals. If someone later claims they became ill from the water, those records are how you show the tub was properly maintained.
• Trained staff. Anyone handling the chemicals needs proper training. It isn’t just a case of dropping in some chlorine tablets and walking away.
• Safe storage. Chemicals have to be stored, labelled and secured so the wrong people can’t get at them.

Get this wrong and it quickly turns into a serious legal liability.

What if I run an Airbnb or holiday let with a hot tub?

If you have an Airbnb or holiday let with a hot tub, take care. Depending on where you are in the world, it may not count as a domestic hot tub at all.

In the UK, a holiday let hot tub is used as part of a business, so it falls under HSG282. Among other things, HSG282 says the water should be replaced every week, or after each group of users if that’s sooner, and that the number of bathers should never exceed the number of seats. Industry guidance for holiday lets goes further. WhatSpa’s hot tub regulations for holiday lets say a domestic-type spa can be used if it’s used by one household at a time and:

• it has at least as many seats as the property sleeps (so a 4-seat tub in a property that sleeps 6 doesn’t meet the standard)
• it ideally has around 250 litres of water per bather
• it can circulate and filter the whole volume within 15 minutes
• it has an inline sanitiser tablet dispenser, and ideally a secondary UV or ozone system
• it has no air blower, unless the air system purges automatically every 12 hours
• it avoids waterfalls, especially ones that can be switched off, because they can create stagnant “dead legs” in the plumbing
• it has fast drainage, because it’ll be drained weekly or between every stay

On top of that come the monthly microbiological tests, quarterly Legionella tests and five years of records. Even this short list shows how quickly the rules add up, and a holiday let is still a long way short of the full rules for a leisure centre. Don’t get caught out. I’ve heard of local authorities turning up at holiday parks to test hot tub water.

In the USA, rules for rental hot tubs vary by state and county, and some treat them as public or semi-public spas. Check with your local health department before you build or list one. If you’re thinking of adding a budget tub to a rental, adding a stock tank hot tub to an Airbnb is a useful read, but check your local rules first.

The liability, and why I don’t design commercial tubs

For me, this is the biggest reason I don’t get involved in commercial hot tubs. I have the expertise to design them, but I don’t want to deal with the red tape, and I certainly don’t want the liability.

There have been cases of people falling ill after using hot tubs at commercial facilities, and in cases like that, liability can be traced all the way back to whoever designed the spa. Even if I design a hot tub perfectly, someone on site could change the plumbing without my knowledge. I design tubs for people all over the world, and I can’t inspect every build in person.

So I stick to what I do best: helping DIYers build the hot tub or plunge pool of their dreams at home. It will work properly, they’re responsible for its upkeep, and I can guide them on water treatment. From there, it’s up to them to follow the guidance.

It costs that much for a reason

Whether you’re the operator, owner, builder or designer, there’s a real liability risk if a member of the public gets ill, or worse, after using your hot tub. What you do in your own home is your responsibility. A commercial setting has strict rules to protect public health, and they exist for a reason. When we visit a commercial spa or pool, we expect it to be built and run to the highest standards of safety and hygiene. Nobody wants to risk their health because of poor design or poor maintenance.

Final thoughts: don’t cut corners

Let me be 100% clear. I design domestic hot tubs and plunge pools. I do not design commercial hot tubs or pools. There’s simply too much red tape and too much liability.

If you’ve landed on my site because a commercial spa builder quoted you $50,000 or more and you’re hoping to cut costs with one of my designs, my advice is simple: don’t. Hire a professional commercial spa builder. Have it built properly. Train your staff. Get it signed off. Do it right, or don’t do it at all.

If it’s for your own home, that’s a different story, and that’s exactly what I’m here for. My DIY hot tub plans cover everything you need for a domestic build, and if you want something custom, I can turn your design into architectural CAD and a 3D plumbing design.

FAQs

Can I use a domestic hot tub in a holiday let?

In the UK, a domestic-type hot tub can be used in a holiday let if it meets HSG282: it’s used by one household at a time, has an inline disinfectant feeder, has its water replaced weekly or between groups, and is tested and recorded properly. Check your local authority’s and insurer’s requirements too.

What is HSG282?

It’s the UK Health and Safety Executive’s guidance on controlling Legionella and other infections in spa pools. It applies to commercial spas and to domestic-type hot tubs used as part of a business, such as holiday lets.

What turnover time does a commercial hot tub need?

Under HSG282, a maximum of 6 minutes for commercial-type spa pools and 15 minutes for lower bather loads. In the USA, the requirement comes from your state or local code.

Does an Airbnb hot tub count as commercial in the USA?

It depends on your state and county. Some treat rental hot tubs as public or semi-public spas. Ask your local health department before you build or list it.

Why don’t you design commercial hot tubs?

The red tape and the liability. Commercial spas need specialist design, sign-off and trained operators, and I can’t inspect builds all over the world. I stick to domestic hot tubs and plunge pools.

Questions about a domestic build? Drop them in the comments below. I read them all. Happy (commercial, but not by me) hot tubbin’!

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