How To Drain A Hot Tub: The Ultimate 2024 Guide

You should drain your hot tub and replace its water every three months as part of its hot tub maintenance routine (and might have to if you ever get foamy hot tub water).

Luckily, it’s easy when you know how.

Here’s our step-by-step guide on how to drain a hot tub, refill it, and get it ready to use again.

How to drain a hot tub

Draining a hot tub is a simple four-step process:

Flush the lines

No matter how clean you keep your hot tub, dirt and grime will eventually build up in the pipes its water passes through.

Turn up the jets to the maximum, then pour the recommended amount of hot tub flush or any other pipe cleaner into the water to clear all the sludge, bacteria or biofilm out of its plumbing. Then allow the jets to run for 15-30 minutes before moving on to the draining process.

This will help keep your spa clean and hygienic, and its chemistry easy to balance. 

Turn your hot tub off

Your hot tub’s pumps will get damaged if they try to run without any water to pass through them. Make sure your hot tub is turned off at the mains before you start draining it to avoid any costly accidents.

Identify the type of drain valves

Check the valve operation before proceeding. A hot tub drain valve is typically operated with a standard ball valve lever that is simply rotated 90° in a direction for opening and closing the drain.

Drain your hot tub water

The only equipment you’ll need to drain hot tub water is a hose pipe. However, you can slash the time it takes to drain by investing in a submersible pump. Here’s how to drain your home spa using either bit of kit:

How to drain your hot tub with a garden hose:

Draining your hot tub with a garden hose is an easy process that requires only a few supplies:

1. Attach an appropriately sized garden hose pipe to your hot tub’s drainage valve or ‘drain spigot’, before leading it to the nearest drain.
2. Ensure that any valves or taps on the primary spigot are in the open position before turning the pump back on at low speed.
3. Open the access panel in your spa’s cabinet and loosen the pump and heater unions to let the water drain from its plumbing lines. 
4. Open the drainage valve, and in an hour or two your spa will be empty.

How to drain your hot tub with a submersible pump:

Draining your hot tub using a submersible pump is relatively quick and easy:

1. Plug your submersible pump into the nearest power supply, run its drainage hose to the drain, and then place it in the deepest point of your hot tub, making sure all power cords are away from any sources of moisture.
2. Open the pump and heater unions in your hot tub’s access panel to drain the water from its plumbing lines.
3. Switch your submersible pump on and it will drain your spa in around half an hour.

Whichever method you use to drain your hot tub, you’ll still be left with some remaining water at the deepest part of your spa.

You can use a wet and dry vacuum to suck up this reminder, which you can then switch to ‘blow’ to force every last drop of water out of the jets and pipes.

Now your hot tub is fully drained and ready to clean or winterise.

How to clean your empty spa before refill

After you drain your hot tub, the best way to make sure it is clean for refilling is by giving the shell a little TLC with a good scrub.

Use a standard cleaning solution, such as mild dish soap diluted in water, and use a damp soft cloth or sponge to wipe down all the internal surfaces such as the seating area, cover, sides of the spa, and surfaces of any added features such as bubblers or fountains.

This will ensure there is no dirty water residue or built-up dirt left on the inner shell before refilling your hot tub!

Additionally, check equipment such as the pump basket, filter compartment and plumbing connections regularly throughout this process.

Cleaning the filter and filter housing

Keeping your hot tub filters and filter housing clean is a breeze when you know the steps.

First, remove the cover to the filter compartment; securely removing any floating items from it.

Next, unlock and take out both the filter cartridge and retainer using its handle, before soaking the filter in a spa filter degreaser or cleaner for around 15 minutes.

Finally, rinse off all the debris from different angles with a hose spray before returning it back to its original slot (just be sure not to over-tighten it).

We have an ultimate guide on how to clean hot tub filters here!

How to refill your hot tub

To refill your hot tub, simply follow these steps:

1. Leave your hot tub turned off until it’s full.
2. Make sure any valves you opened to drain it are closed.
3. Run your hose pipe through the top of your spa’s filters to avoid an air lock forming in the pipes.
4. Turn your hose on and fill your hot tub up to the fill line.

Once your home spa is full it’s time to balance its water chemistry. Add chlorine or bromine granules or tablets according to the manufacturer’s instructions, aiming for a Free Chlorine level of 2-5mg/l or a Total Bromine level of 3-6mg/l.

If you want your hot tub back in action as quickly as possible, you might also want to use a hot tub shock.

Once you’ve added sanitiser to your hot tub, use a hot tub test strip to check and adjust its pH levels to 7.2-7.6 and Total Alkalinity (TA) to 125 – 150mg/l.

Then all that’s left to do is change into your swimming costume and enjoy a soak!

Frequently Asked Questions:

What is the fastest way to empty a hot tub?

The quickest way to empty a hot tub is to use a submersible pump. This type of pump will usually have an inlet and outlet hose attachment and is designed specifically to make draining your hot tub faster.

Before starting, ensure the electrical cord is far away from any puddles. Hand pumps are also available but require physical labour, thus they are not as fast or efficient at emptying large quantities of water as submersible pumps.

How often should you drain your hot tub?

Generally, hot tubs should be completely drained for cleaning and hot tub maintenance every three to four months. When draining your hot tub, it is important to clean the walls and filters of caked-on contaminants that accumulate over time.

After draining the water, consider using fresh water from a hose to give the entire inside of the hot tub a good rinse. This helps remove everything from excess soaps or salts from chemical treatments to general dirt and grit.

During this time you can also wipe down the spa surface with PH-balanced cleaners if necessary to ensure your spa remains sanitary and ready for use.

How long does it take to empty a hot tub with a garden hose?

Depending on the size of your hot tub, it can take anywhere from 20 minutes to several hours to fully drain a hot tub using a standard garden hose. The amount of time needed is based on the capacity size and pump system within the hot tub.

Generally speaking, you can expect to have your hot tub emptied within an hour if you’ve got a standard-sized one with the correct connected hoses.

Can you empty hot tub water onto a garden?

Generally speaking, it is not recommended to empty your hot tub water directly onto a garden. Hot tub water contains high levels of chlorine, which can be detrimental to plants and flowers when absorbed through the roots, potentially leading to wilting, discolouration, or weakened root systems and stems in your garden.

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