What are the Differences Between Domestic and Commercial Hot Tubs?

Differences Between a Domestic Hot Tub and a Commercial Hot Tub

Differences Between Domestic and Commercial Hot Tubs? If you are wondering what the differences are then read on. Whilst they may seem similar, there are some pretty distinct differences. Without trying to go into too much detail, this article will try and give you an overview of the main differences.


I design hot tubs for domestic use only – there is a reason for this and hopefully by the end of this article you will understand more. For videos on domestic hot tub building check out my YouTube Channel

Differences Between Domestic and Commercial Hot Tubs – The Design


In its most basic form, there is a fundamental design difference between a commercial hot tub and a domestic one.


Commercial Hot Tubs are usually overflow spas that have a balance tank to store the water that is displaced by the bathers. The reason for this is that you can never be sure how many bathers are going to be in the tub at once.


Whilst you might have a sign on the wall that says maximum of 10 for example – if your balance tank is not big enough when 12 people get in where does the water go? Last thing you want is it flooding your facility, so you have to have the balance tank designed accordingly.


This is different from a domestic hot tub which usually involves a skimmer (unless it is an infinity tub). With a skimmer, you use the skimmer to allow for the displacement of the bathers. You will know what the maximum number of bathers will be at any one time in your own tub, so you can allow for the right amount of displacement and the skimmer helps take up the slack on this one.


Remember, each adult will displace around 70 litres or 15 gallons when they get into the tub.


Rules and Regulations are different for Commercial and Domestic Hot Tubs.


This is the part that gets really tricky and is one of the main reasons that I don’t get involved in commercial designs. Differences Between Domestic and Commercial Hot Tubs a lot is down to the rules and regulations.


If you have a hot tub in your own home, it is up to you how you look after the water. It is up to you how you clean your filters. It is up to you how often you change your water. However, in a commercial setting, these rules and regulations will be different. They are there for the safety of the bathers.


With the breadth of audience that this blog has, I don’t want to cover specific rules in different countries and States, I just want to make you aware that there are rules to adhere to and they can be pretty strict. I will however, give some examples below.


There are also fines and penalties for not adhering to these rules so you want to be careful. Below are a couple of examples.


Water Turn Over Time


Water turnover rate is the amount of time that it takes all of the water in a tub to pass through the filter. This turnover time is totally different for domestic and commercial use. Again, in domestic, you can set your own filter cycles on your spa pack. 20mins, a couple of times a day is more than enough.


In a commercial setting, this turnover time really depends on the average number of bathers that you expect to be in the tub. You have to demonstrate that the plumbing and equipment is able to keep up to these numbers. It could be as little as 10 mins – so the whole tub needs to go through the filter every 10 minutes.


This leads to much larger pipework. Much larger pumps and filters as the domestic kit is just not designed to move the amount of water that is needed to hit these target turnover rates.


Water Flow Rates


Water fallow rates for domestic use is all about getting all of the jets to work when you want them to. In a commercial setting it is much more than this.


You will have a set amount of flow that must be maintained to aid the turnover times. If you design a plumbing layout you need to demonstrate by calculation and physical testing that the flow is maintained. Big pipes, big pumps – this is commercial standard.


This can be a problem because what happens if during the building process, the plumber adds a couple of extra 90 degree bends into the layout as he or she made a mistake – flow rates drop and you could be in trouble.


It is such a fine line on commercial tub design you have to get it right.


Chemical Treatment


Chemical treatment in a domestic setting is all about keeping your water clean and healthy. Testing once a week, bit of chlorine here and there – it is not rocket science.


Commercial chemical treatment is a whole new ball game. Firstly, it is generally expected that there is a full auto dosing system that will maintain the water continuously. PH Levels, Sanitiser Levels, all should be maintained automatically.


For reporting purposes, there is usually a log that keeps a record of the levels at a particular time – you may need this if there is a problem and someone gets ill for example and claims it is because of your water and you need the historical data to back this up that it was not you at fault.


Furthermore, all staff that handle the chemicals have to be trained by professionals. It is not just a case of throwing in a few chlorine tablets and moving on in a commercial setting. Likewise, the chemicals all need to be properly stored and labelled and the access to said chemicals all monitored.


This, if not done correctly can be a total litigation minefield.


What if I run an Air BnB or holiday let and Have a Hot tub?


If you have an Air BnB and a Hot Tub then be warned. Depending on where you are located in the World, you could come under different classification than a domestic tub.


For example, in the UK, an Air BnB or holiday let rental is not classed as a domestic tub and there are different standards you need to meet – HSG282 to be exact.


I don’t want to go into too much detail here (and also I am not an expert on this) but for example, if you have a 4 person hot tub, but you have an Air BnB that sleeps 6 then this does not meet the specific standard…..


According to WhatSpa


If there’s only ever going to be a household’s worth of people in your holiday let’s hot tub then you’re fine to use a domestic portable spa, as long as it meets the technical requirements laid down by HSG282, such as:

  • The capacity of the hot tub (its number of seats) is at least equal to or more than the berth capacity of the accommodation.
  • The hot tub should ideally have a water capacity equal to 250 litres per bather.
  • The hot tub should be capable of circulating and filtering the total water volume within 15 minutes.
  • It should be equipped with an in-line sanitiser tablet dispenser.
  • It should ideally be equipped with a secondary UV or Ozone system to oxidise the water as it passes through the circulation system.
  • The hot tub should not be equipped with an air blower unless there is a provision for automatically purging the air system every 12 hours.
  • Waterfalls are not recommended, especially if they can be turned off, as this can create plumbing system ‘deadlegs’ where water can become stagnant and contaminated.
  • Fast drainage facilities are also desirable since the hot tub will need to be fully drained either weekly or in between each guest stay (whichever is shortest).



Even in this short example here you can see that the list of rules is starting to add up. This is just for a holiday let or Air BnB – this is not even close to commercial rules and regulations.


These standards are different to those of a commercial leisure centre for example, but they are not the same standards as domestic.

So don’t get caught out. Do your research and abide by the rules. I have heard of one local authority purchasing a whole bunch of rapid testing kits for hot tubs and they were going to go around the holiday parks in the area testing the tubs chemical levels – fines ahoy! Be warned.



Differences Between Domestic and Commercial Hot Tubs – The Liability


For me, this is the main reason why I don’t get involved in commercial tubs. I am more than capable of designing them, I just don’t want the red tape and I don’t want the liability.


There have been cases where consumers have taken ill due to using a hot tub in a commercial facility.


The liability and culpability can be passed all the way backwards to the person or company that actually designed the spa in the first place – this for me is why I am not interested in this section of the market.


If I have designed it correctly then someone on site had made changes without my knowledge to the plumbing (I design all over the world so cannot physically check every build) this would be a problem.


I will stick with what I do best – helping the DIYer at home build the hot tub or plunge pool of their dreams. It will work fantastically, they will take care of it, I can help educate them on the water treatment and it is down to them to follow the guidance.



It is that price for a reason.


As I have mentioned above, as the operator, owner, builder and ever designer, there is a potential liability if a member of the public gets ill or worse in your hot tub. The rules are very different for domestic and what you do in your own home is largely your own responsibility.


The rules are there for a reason. To keep up safe when we go to a commercial pool or a spa – we want to know that the pool and tubs have been built to and maintain all the local standard for safety and hygiene.


Differences Between Domestic and Commercial Hot Tub rules exist for a reason


In Conclusion – Don’t Get Caught Out Trying to Cut Corners


I want to put this out there. I design domestic hot tubs and plunge pools; I do not design Commercial grade tubs and pools. For me, there is just too much red tape and potential liability.


If you have found my website because you have been quoted $50K+ by a commercial Spa builder for your commercial facility and you are trying to save a few bucks / quid by using my designs – then my advice is don’t!


Have it built for you. Have it built correctly. Have your staff trained and have it all signed off.


Do it right or don’t do it at all.


Happy “commercial but not by me” Hot Tubbin’



Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

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.

Today, I've helped over 1000 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

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