What are the Differences Between Domestic and Commercial Hot Tubs?

If you’re wondering what sets domestic and commercial hot tubs apart, you’re in the right place. While they may look similar, there are some key distinctions worth noting. Without diving too deep into technical details, this article will give you a clear overview of the main differences.

I design hot tubs specifically for domestic use—and there’s a good reason for that. By the end of this article, you’ll have a better understanding of why. For step-by-step guides on building your own hot tub, check out my YouTube Channel.

Differences Between Domestic and Commercial Hot Tubs – The Design

At its core, one of the biggest distinctions between a commercial and a domestic hot tub comes down to design.

Commercial hot tubs are typically overflow spas equipped with a balance tank to store the water displaced by bathers. This is essential because you can never predict exactly how many people will be in the tub at once.

Even if there’s a sign stating a maximum capacity—say, 10 bathers—what happens if 12 people jump in? If your balance tank isn’t large enough, that extra water has to go somewhere. The last thing you want is water flooding your facility, so the balance tank must be designed to accommodate these fluctuations.

This setup differs from a domestic hot tub, which usually relies on a skimmer (unless it’s an infinity tub). With a skimmer system, water levels adjust naturally to account for bathers getting in and out. Since you control how many people use your home hot tub at any given time, you can plan for proper displacement, and the skimmer helps manage the overflow.

Keep in mind—each adult displaces around 70 liters (15 gallons) of water when they enter the tub!

Rules and Regulations for Commercial and Domestic Hot Tubs Differ

This is where things get complicated and one of the biggest reasons why I steer clear of commercial hot tub designs. When comparing domestic and commercial hot tubs, a lot comes down to rules and regulations.

If you own a hot tub at home, you’re in full control of how you maintain the water, how often you clean the filters, and when you decide to change the water. However, in a commercial setting, these regulations are much stricter—and for good reason. They are designed to ensure the safety of bathers.

Since this blog reaches a wide audience, I won’t dive into the specific rules that vary across different countries and states. Instead, I just want to highlight that strict regulations exist, and they must be followed. To give you an idea, here are a few key examples:

Additionally, there are fines and penalties for failing to comply, so it’s crucial to be aware of these regulations.

Water Turnover Time

Water turnover rate refers to how long it takes for all the water in a tub to pass through the filter. This requirement varies significantly between domestic and commercial use. For home hot tubs, you can customize your filter cycles in the spa pack—20 minutes a couple of times a day is generally enough.

In a commercial setting, turnover time depends on the expected number of bathers. You must prove that the plumbing and equipment can handle these numbers. It could be as short as 10 minutes, meaning the entire tub’s water must be filtered every 10 minutes!

To meet this requirement, commercial hot tubs require much larger pipes, pumps, and filters. Standard domestic equipment simply isn’t built to move the volume of water needed to maintain these strict turnover rates.

Water Flow Rates

For home hot tubs, water flow rates are mostly about ensuring that the jets work properly when needed. In a commercial setup, however, it’s far more complex.

Commercial hot tubs must maintain a specific flow rate to support the required turnover times. When designing the plumbing system, you need to provide both calculations and physical tests to prove that the flow is consistent. Larger pipes and bigger pumps are a must for commercial standards.

This also introduces potential issues. For example, if a plumber accidentally adds a few extra 90-degree bends to the pipe layout during construction, the flow rate could drop—which could lead to compliance issues.

Commercial hot tub design is a delicate balancing act—there’s little room for error, so everything must be done right from the start.

Chemical Treatment: Domestic vs. Commercial

In a home hot tub, chemical treatment is all about keeping the water safe and clean. Testing once a week, adding a bit of chlorine when needed—it’s pretty straightforward.

Commercial hot tub chemical treatment, however, is an entirely different challenge. First, it’s generally required to have a fully automated dosing system that continuously monitors and maintains water quality. pH levels, sanitizer levels—everything must be controlled automatically.

For compliance and safety, most commercial facilities must keep a log that records chemical levels at set intervals. This record can be crucial if an issue arises—for instance, if someone claims they got sick from the water. Having historical data can help prove that proper maintenance was followed and that your facility was not at fault.

Additionally, any staff handling chemicals must receive professional training. In a commercial setting, it’s not as simple as tossing in a few chlorine tablets and moving on. All chemicals must be properly stored, labeled, and monitored to ensure compliance and prevent unauthorized access.

If these regulations aren’t followed correctly, it can turn into a serious legal liability. 

What if I Run an Airbnb or Holiday Rental with a Hot Tub?

If you have an Airbnb and a hot tub, then take caution. Depending on where you are in the world, your hot tub may fall under a different classification than a standard domestic tub.

For example, in the UK, an Airbnb or holiday rental hot tub is not considered domestic, and you must meet specific regulations—HSG282, to be exact.

I won’t go into too much detail here (and I’m not an expert on this), but here’s an example: if you have a 4-person hot tub but your Airbnb sleeps 6 guests, then it does not meet the required standard.

According to WhatSpa:

• If your holiday rental’s hot tub is only used by a single household at a time, you can use a domestic portable spa as long as it meets HSG282’s technical requirements, such as:
  • The number of seats in the hot tub must be equal to or greater than the accommodation’s sleeping capacity.
  • The hot tub should ideally have at least 250 liters of water per bather.
  • The total water volume must be fully circulated and filtered within 15 minutes.
  • The hot tub must have an in-line sanitizer tablet dispenser.
  • It should ideally have a secondary UV or ozone system to oxidize the water as it circulates.
  • Air blowers are not recommended unless they have an automatic purge system every 12 hours.
  • Waterfalls are also discouraged, especially if they can be turned off, as they may create stagnant ‘dead legs’ in the plumbing that can lead to contamination.
  • Fast drainage systems are recommended, as the hot tub must be fully drained weekly or between guest stays—whichever is sooner.

Even this short list shows how quickly the rules start to add up. And this is just for an Airbnb or holiday rental—it doesn’t even come close to full commercial regulations.

These rules are different from those for commercial leisure centers, but they are stricter than standard domestic guidelines.

Don’t get caught out. Do your research and follow the regulations. I’ve even heard of local authorities conducting random hot tub chemical tests in holiday parks—issuing fines left and right! Be warned.

 

 

 

Differences Between Domestic and Commercial Hot Tubs – The Liability

For me, this is the biggest reason why I don’t get involved in commercial tubs. I absolutely 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 multiple cases where consumers have fallen ill after using a hot tub in a commercial facility.

In such cases, liability can be traced all the way back to the person or company that originally designed the spa. This is exactly why I have no interest in this part of the market.

Even if I design a hot tub perfectly, someone on-site could make unauthorized changes to the plumbing without my knowledge. Since I design tubs for people all over the world, I can’t physically inspect every build—this could lead to serious issues.

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

It Costs That Much for a Reason

As I’ve mentioned before, whether you’re the operator, owner, builder, or even the designer, there’s a real liability risk if a member of the public gets sick—or worse—after using your hot tub. The rules for commercial and domestic tubs are vastly different. What you do in your own home is your responsibility, but in a commercial setting, there are strict regulations in place to protect public health.

These rules exist for a reason. When we visit a commercial spa or pool, we expect it to be built to the highest safety and hygiene standards. No one wants to risk their health due to poor design or improper maintenance.

Differences Between Domestic and Commercial Hot Tubs Exist for a Reason

Final Thoughts – Don’t Cut Corners

Let me be 100% clear—I design domestic hot tubs and plunge pools. I do NOT design commercial-grade tubs and pools. There’s simply too much red tape and liability involved.

If you’ve landed on my site because you were quoted $50K+ by a commercial spa builder and you’re hoping to cut costs by using my designs—my advice is simple: DON’T.

Hire a professional commercial spa builder. Have it built correctly. Train your staff. Get it properly signed off.

Do it right—or don’t do it at all.

Happy (Commercial, but Not by Me) Hot Tubbin’

—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