How to flush, drain & refill your hot tub

7 MIN READ

Hot tubs require regular maintenance to keep your hot tub in great condition, as well as making sure the water is crystal clear and safe for bathers. Whether you are using sanitisers such as chlorine or bromine, or are using an ozone or a salt system, we recommend you drain and refill your hot tub periodically and flush the pipes to help keep your hot tub clean. Ever wondered why hot tubs require draining? In this info guide we’ll explain this as well as how to drain your hot tub, how to flush the pipes and how to refill it!

Why do I need to empty my hot tub?

A good reason to drain your hot tub is to flush out the pipework and give your hot tub a deep clean. This will ensure there is no bacteria or stuck in the pipework and will make sure your water stays clean and fresh when you refill it. We will explain how to do this below.

Another reason to empty your hot tub periodically is because of TDS (Total Dissolved Solids) build up. Very rarely tested in domestic hot tubs, TDS measures everything that is dissolved in hot tub water including chemicals (PH balancers, chlorine, bromine etc), organic matter from bathers and anything else that has found its way into your hot tub water. Water can become very saturated and difficult to work with when the TDS gets too high. The following are signs your TDS may be too high:

  • Struggling to balance pH levels
  • Using more chemicals than usual
  • Water smells or is tinted
  • Scale build up on the shell of your hot tub

There are ways to prevent TDS getting too high, however once it is high the only way to reduce TDS is to drain your hot tub and refill it with fresh water.

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How to flush & clean your hot tub pipework

Before draining your hot tub, it is a good idea to give your pipework a thorough clean with Pipe Cleaner to remove any dirt or bacteria that may have built up in the pipes. Follow the instructions on the packaging of the product. Below is an outline on how to use hot tub pipe cleaner:

  • Remove the filters from your hot tub
  • Turn all the jets on
  • Pour the recommended amount of pipe cleaner into the filter housing.
  • Allow the jets to run for a cycle (usually 15 -30 minutes).
  • Then drain your hot tub, following the instructions below.

How do I drain my hot tub?

All hot tubs have a drain valve to release the water. This is a very simple way to empty your hot tub, however it can take a few hours. The other way to drain your hot tub is by using a submersible pump which is a lot faster.

How to drain your hot tub using a drain valve

Your hot tub drain valve is conveniently plumbed into your hot tub and therefore is the simplest way to drain out the water.

  1. Make sure you have flushed your pipework before draining.
  2. Turn your hot tub off at the circuit breaker. It is important to make sure there is no power to the hot tub as damage can be caused should pumps and jets run while there isn’t any water in the hot tub.
  3. Make sure the area you are draining the water to has the capacity to hold the volume of water in your hot tub. The water is perfectly safe to be emptied on to grass, however it may be worth drain the water to an existing drain using a hosepipe to avoid a muddy garden.
  4. Next, locate your drain valve. This is usually situated at the bottom of the front panel on your hot tub, sometimes it will be on a bottom corner.  Depending on the make and model of your hot tub, it may have two valves, a primary and auxiliary. Use the primary to drain most of the water, and then open the auxiliary to drain the internal bleed lines. This is particularly important if you are draining your tub to winterise it. Click here to learn how to winterise your hot tub.
  5. Attach your garden hose to the drain valve if necessary.
  6. Open the ball valve on your spigot so the water can drain.

How to Drain a Hot Tub using a Submersible Pump

A submersible pump is a great way to drain your hot tub faster. Submersible pumps can be found in DIY or tool shops and can drain a hot tub in as little as 10 minutes, depending on size.

  1. Make sure you have flushed your pipework before draining, as above.
  2. Turn the power to the hot tub off at the circuit breaker. It is important to make sure there is no power to the hot tub as damage can be caused should pumps and jets run while there isn’t any water in the hot tub.
  3. Place your submersible pump in the hot tub footwell or at the deepest point of your hot tub.
  4. Make sure the area you are draining the water to has the capacity to hold the volume of water in your hot tub. The water is perfectly safe to be emptied on to grass, however it may be worth drain the water to an existing drain using a hosepipe to avoid a muddy garden. Run the hose to your selected area.
  5. Connect the pump to power, turn it on and let the hot tub drain.
  6. When the hot tub is empty, turn off the pump and remove it from the spa. Please note: Some pumps have float switches that will cut the pump off when the water goes below a certain level. Read through the pump manual before use.
  7. You can either use a wet and dry vacuum on the jets to make sure there is no dirty water left, or run the hose through the jets to rinse them out. 

Once your hot tub is empty, use a clean soft cloth to wipe the shell and filter compartment down. Now is also a good time to clean your hot tub filters.

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How do I refill my hot tub?

Quick and easy, refilling your hot tub doesn’t require any specialist equipment, just a hosepipe long enough to reach it! Simply, place your hosepipe directly into the filter housing and turn it on. Filling your hot tub through the filter housing will fill the pipework first and reduce the risk of an air lock. An air lock is where air is trapped in the pipework and will not allow the water to flow properly. Your control panel may show a "flow" error when this occurs. Get in touch with us if you need any help with your control panel.  Once your hot tub is filled you can turn the tap off, this can take a few hours depending on water pressure. We’d recommend filling your hot tub so the water level sits between the top jets and the bottom of the pillow, this way you will be fully submerged when you sit in your hot tub.

Hot tub draining and refilling – Your questions answered.

Can you drain hot tub water on to grass?

Hot tub water is very unlikely to damage your lawn. If you are concerned or have a newly set or delicate lawn then we’d recommend leaving the level in your hot tub water to drop to 0 before emptying it on to grass. Alternatively, use a hose pipe to direct the water to a drain. This will also prevent your grass getting muddy.

We hope we’ve answered your questions about flushing, draining, and refilling your hot tub. However, if there is anything else we can help you with, please get in touch with the team on 0800 368 9840.

Here are some chemicals you may need while flushing, draining & refilling your hot tub...

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Jacuzzi® Hot Tub Surface Cleaner
Pack size: 1L Delivery within 48 hours if ordered on a weekday before midday. Jacuzzi® Hot Tub Surface Cleaner is the perfect addition to you Hot Tub cleaning routine, as it is designed t...
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Life Spa Hot Tub Brush is a great addition to your hot tub cleaning kit! Specifically designed for spas and hot tubs, the soft bristles remove dirt and scum from your hot tub effectively,...