How to drain a hot tub: a step-by-step guide

Asking how to drain a hot tub? Here’s the lowdown on completing this essential maintenance

how to drain a hot tub - couple in hot tub on patio
(Image credit: Lay-Z-Spa)

The question of how to drain a hot tub is an important one. A hot tub is a fabulous addition to any backyard, providing relaxation in the fresh air year round, but your spa does need a little TLC from time to time.

Regularly draining the hot tub is one of the jobs that should be on your agenda to maintain the water quality. Once it’s empty, cleaning is easy, and the water can then be replaced so the spa is a pleasure to step into every day. 

Once you’ve finalised your hot tub ideas for your outside space, discover how to undertake this essential task with our step-by-step guide and advice from the experts.

How to drain a hot tub

If you've recently invested in one of the best hot tubs, you might be wondering why you need to know how to drain a hot tub, and the answer is that it’s a question of the quality of the water inside it.

‘It’s important to drain a hot tub regularly for a number of reasons,’ explains Sallie Leslie-Golding from BISHTA (The British and Irish Spa and Hot Tub Association). ‘A hot tub is a relatively small body of water with a relatively high concentration of bathers (certainly when compared, for example, with a swimming pool). Sanitizing chemicals are added to the water to control potentially harmful microorganisms and deal with other pollutants that can enter the water during use. Over time, the water chemical balance becomes harder to manage, and it loses its characteristic sparkle and becomes lank and lifeless.’

A further reason why you should do this as part of your hot tub maintenance? ‘Draining the water from the hot tub is a really good opportunity to give everything a thorough clean to keep it in tip-top shape,’ says Tom Drakett-Cain, brand marketing manager at Lay-Z-Spa.

Here are the steps you need to follow to drain your hot tub.

1. Flush the pipes

You want to know how to drain a hot tub, but before you do so, there is a cleaning routine you should follow while it is still full of water. Using an additive called a system or line flush will clean up the contaminants that build up inside the plumbing lines.

Follow the pack instructions including timings before draining the hot tub.

2. Turn the hot tub off

To drain a hot tub, you need to turn the power off by unplugging it completely or turning it off at the circuit breaker. The pumps and jets should not run when there is no water in the spa.

built in hot tub on a patio in a garden

(Image credit: MySpa)

3. Drain using a hose or submersible pump

There are actually two answers to the question of how to drain a hot tub. You can do it using a garden hose, or a submersible pump. It’s worth investing in the latter if you want to get the job done much more quickly.

  • Drain a hot tub with a hose
    Locate the drainage valve of the hot tub, and connect the garden hose and run this to a drain. Open the valve to allow the water to drain out. Be aware that the process may take an hour or so or even up to two hours.
  • Drain a hot tub with a submersible pump
    Plug in the pump, connect its drainage hose, and run this to the drain. Place the pump in the deepest part of the hot tub and switch on. Allow to drain but pay attention to the water level so you can switch off the pump when the water has been removed unless it is a design that will do so automatically. After use, disconnect the hose and allow the pump and hose to dry before storing.

4. Clean the hot tub

Once the water is drained, it's important to learn how to clean a hot tub properly before refilling it with water. Use a cleaning product designed for hot tubs and follow the manufacturer's instructions. ‘The whole hot tub, inside and out, should be cleaned once it has been drained to effectively remove any dirt, grime, and bacteria lurking,’ says Tom Drakett-Cain.

This includes the filter. ‘Don’t forget to clean the filter,’ says Tim Snelling from Hot Tub Hub. ‘A simple job, but often one that is overlooked and can affect the sanitation of your tub. Ensure you give the filter a deep clean when you drain your hot tub, alongside weekly rinses to ensure optimum hot tub cleanliness.’

man cleaning an empty hot tub

(Image credit: Christine Kohler/Getty Images)

How often to drain a hot tub

Now you know how to drain a hot tub, the question of how frequently you should be doing so is the next one. ‘Ideally, the water should be drained every three months and refilled with fresh,’ says Tom Drakett-Cain. This means that if you're using it all year long, you'll need to make sure it's part of your hot tub winter care too. 

Bear in mind that you may need to do so more frequently, however. Consider draining, cleaning and refilling the hot tub after periods of heavy use, if the water has become cloudy or if, despite chemical treatment, the water doesn’t have its usual life.

tow men sitting in a hot tub in a garden

(Image credit: Lay-Z-Spa)

Hot tub draining mistakes and how to avoid them

These are the errors the experts see most often in the hot tub drainage process so you can avoid them.

  • Forgetting to turn off the power
    ‘As the water level drops as it’s emptied, jets that are normally underwater become exposed and can spray water copiously over any unsuspecting bystanders if the power is still on, which normally serves as a fairly vivid reminder to turn the power off,’ says Sallie Leslie-Golding.
  • Failing to drain the water to the right location
    ‘Special care should be taken to ensure the water goes into a drain,’ says Tom Drakett-Cain. ‘The water from a hot tub can be harmful to grass, plants, animals, and insects due to the levels of chemicals in the water.’ Be mindful that you should never discharge the water into a storm drain; check with your water company to be sure of where you can discharge it.
  • Using the wrong tools for cleaning
    ‘As tempting as it seems, we would not recommend using a pressure washer to clean your hot tub filter as this may damage the filter. A standard garden hose will do the job nicely,’ says Tim Snelling.
Sarah Warwick
Sarah Warwick

Sarah is a freelance journalist and editor writing for websites, national newspapers, and magazines. She's spent most of her journalistic career specialising in homes and gardens – long enough to see interiors that blur the indoor/outdoor link become a must-have. She loves investigating the benefits, costs and practicalities of home improvement, both indoors and out, and it's no big surprise that she likes to put what she writes about into practice, so she's a serial house revamper.