Share This


How long can you leave water in a hot tub? (Risks, advice and more)

July 7, 2023

Estimated read time - 6 minutes

Author – Fin Green – Content Creator UK, Jacuzzi Group 

Are you are in the process of purchasing a hot tub and wondering how often you need to drain and refill it? Already an owner and simply wondering how long is too long to keep water in a hot tub?

This article will delve into everything you need to know about why changing the water in your hot tub is so important. By the time you reach the end, you will know exactly when to do it and gain some expert tips along the way!

What chemicals do I need for a hot tub? Guide, helpful tips and more

Do I need to check on my hot tub water? 

Yes, you do need to check your hot tub water.

Water in a hot tub can generally be left in for several months but will still need to be checked and changed. How often comes down to your maintenance and cleaning schedule, and the quality of the water.  

It is also important to regularly check and adjust the chemical balance and disinfection levels, as well as clean and maintain the filters. This will ensure the water remains safe and clean. 

How often do you need to change water in a hot tub? 

Usually, the water should be replaced every 3 to 4 months, but this timeframe may differ depending on usage, upkeep, and water quality.  

You’ll find that monitoring pH levels, alkalinity, and sanitiser levels through regular testing will make it clear to you when it’s time to change the water.  

Consistent water maintenance, cleaning, and filter maintenance are also key in prolonging the lifespan of your hot tub water. 

Want to learn more about hot tub water maintenance and what needs cleaning every few days, weekly, monthly and quarterly? We recommend you read this article for more information. 

What happens if you leave water in a hot tub? 

If you don't change the water in a hot tub for extended periods of time, it can lead to several problems: 


Poor water quality  

Over time, the accumulation of body oils, sweat, lotions, and other contaminants can lead to poor water quality. This can result in cloudy, foamy, or discoloured water, which is unappealing and potentially unsafe for use. 

Toal dissolved solids in your water can also become an issue. The solid chemicals that dissolve in your water never completely disappear, leading to poor water quality over time if water is not replaced sufficiently.


Increased bacterial growth 

Stagnant water without regular sanitisation and filtration can become a breeding ground for bacteria, algae, and other microorganisms.  

This can lead to unpleasant odours, skin irritation, and potential health risks for users. 


Difficulty in maintaining proper chemical balance 

As the water ages, maintaining the desired pH levels, alkalinity, and sanitiser levels can become a challenge. This can make it harder to maintain a safe and comfortable environment for any users of your hot tub.


Reduced efficiency of equipment 

Old, motionless water can lead to the buildup of mineral deposits and debris. This can potentially clog filters, jets, and other equipment. It can also reduce the efficiency and lifespan of the hot tub components and may even result in some costly repairs or replacements. 


Ultimately, the longer you go without changing the water in a hot tub, the more difficult it becomes to maintain clean and safe conditions for use. Regular water changes, along with proper maintenance and chemical treatment, are crucial for optimal performance and enjoyment of your hot tub. 

Clean hot tub water

How long can I leave the water in my hot tub if it is turned off? 

The length of time you can leave water in a switched-off hot tub varies, depending on the temperature, water quality, and the tub's specific design.  

Generally, it is recommended not to leave water in a hot tub for more than two to four weeks, as stagnant water can become a breeding ground for bacteria and algae.  

To maintain water quality and prevent any potential issues, it is best to drain your hot tub if it will not be used for an extended period, then fill it up when you are ready for use again. 

Can I leave water in my hot tub over winter? 

You can leave water in your hot tub over winter all you like if you are going to be using it. If you stick to your regular maintenance, then all should be fine. 

Leaving your hot tub over winter and not using it can lead to some serious issues. You will need to winterise your product if it not going to be used over winter. Here are some key points to consider: 


Freeze protection 

Freezing temperatures can cause significant damage to a hot tub, including cracked pipes, pumps, and other equipment.

Ensure that your hot tub has proper insulation and that you take steps to prevent freezing, such as using a freeze protection system, adding antifreeze, or draining the water from the plumbing lines. 


Covering and protecting the hot tub 

Use a high-quality, well-insulated cover to protect the hot tub from debris, snow, and extreme cold. Ensure the cover is secured properly to prevent damage from strong winds. Additionally, regularly remove snow accumulation from the cover to prevent excess weight. 


Check the manufacturer's guidelines 

It's essential to follow the specific recommendations provided by the hot tub manufacturer for winterisation and extended periods of non-use. These guidelines will help ensure the longevity and proper functioning of your hot tub. 


If you plan to leave water in your hot tub over winter, it's important to take the right measures to protect the tub and prevent freezing. Proper winterisation and maintenance are key to avoiding damage and ensuring you can enjoy your tub safely once the winter season is over. 

To learn more about using your hot tub over winter, read this article: 

Using test strips for a hot tub

How long can you leave water in a hot tub without chemicals? 

The specific duration that water can be left without chemicals varies depending on factors such as water quality, temperature, and environmental conditions.


As a general guideline, it is advised that you treat the water with appropriate sanitisers and maintain the proper chemical balance regularly, even if your hot tub is not in use.  

This helps prevent the growth of harmful bacteria and ensures the water remains safe and clean for future use. 

You can find out more about hot tub chemicals and how to use them by reading here. 

Can I leave water in my hot tub if there is a hosepipe ban? 

You may find yourself not being able to change the water in your hot tub due to a hosepipe ban, depending on what area you live in. The most recent one being the South West and South East bans which is preventing customers from using their hosepipes - including for recreational hot tub use. 


This can be an issue for you as a hot tub owner, depending on how long the said ban is in place for, but there are some solutions.

Expert tips to make your hot tub water last longer

If you're wondering what the best practise is to extend the time between hot tub water changes, we recommend you: 


1 - Regularly maintain water balance 

Properly balancing the water chemistry in your hot tub can significantly extend the lifespan of the water. Test  and adjust the pH, alkalinity, and sanitiser levels regularly to keep them within recommended ranges. This helps prevent the growth of bacteria and algae. 


2 - Use a hot tub cover 

A high-quality, well-insulated hot tub cover can help retain heat, reduce evaporation, and keep debris out of the water. By minimising evaporation, you can decrease the amount of water lost over time and prolong the need for a water change. 

3 - Encourage proper hygiene 

Encourage hot tub users to rinse off before entering the tub to reduce the introduction of body oils, lotions, and other contaminants. This can help maintain water quality and reduce the build-up of organic matter, which can lead to the need for a water change. 


4 - Regularly clean and maintain the filtration system 

Routinely clean or replace the filters in your hot tub to ensure optimal filtration. By keeping the water clean and free from debris, the need for water changes can be reduced. 


5 - Minimise water contamination 

Encourage anyone using the hot tub to avoid bringing in food, drinks, or other substances into the hot tub that can contaminate the water. Another simple measure is to avoid activities that can lead to excessive splashing, dirt and debris. This can help prolong the cleanliness of the water. 

These steps also count for general hot tub maintenance in general - the more steps you take, the less often you should need to change your hot tub water. 

Realise there are some products you need to buy or stock up on? Browse our products available on Jacuzzi® Shop. 

Clean hot tub water


A summary of how long you can leave water in a hot tub depends on a couple of factors. You need to take extra care of your hot tub water and take extra steps than usual when: 

  • It’s winter 
  • You are using your hot tub frequently  
  • It is turned off 
  • You may not be able to change it for an extended period of time 

Afterall, looking after your water is an essential part of being a hot tub owner. Proper water maintenance can lead to a longer lifespan of your product, and more bubbly fun. A win-win situation! 

While we’re on the subject of water, are you wondering how long a hot tub takes to heat up, whether it’s after it’s delivered to you, or after you’ve drained and refilled it? This article covers these questions and more.  

Still have some questions? You can speak to a member of our expert teams at one of more than 30 locations around the UK? Click the link below to find your nearest showroom or head to Jacuzzi® Shop for any hot tub water maintenance products you may need.