How To Drain & Refill Your Hot Tub

No matter how well you take care of your hot tub water, eventually you will have to replace it with fresh water. In this article we will explore why you need to drain and refill your hot tub, and show you the best way of doing it.

Why Do You Need To Drain Your Hot Tub?

The more a hot tub is used and the more chemicals are added to the water, the more minerals dissolve and build up in the water. Water dissolves and holds minerals – known collectively as Total Dissolved solids or TDS – until it becomes saturated and cannot hold any more. While not harmful, saturated water will affect your hot tubbing experience in three ways:

• The water will have a slightly harsher feel to it.
• The water will look hazier than normal.
• Chemicals added to the water won’t dissolve as easily as they would in fresh water. This makes the water harder to balance.

If you find that your hot tub water just doesn’t seem to stay clear, foams excessively, or just doesn’t feel “fresh” anymore, chances are it’s time to change the water.

Draining the water in your hot tub does two things:

• It allows you to add in fresh water, which will improve the reduce the TDS and improve your overall bathing experience.
• It gives you an opportunity to clean the shell and plumbing of the hot tub, which will further improve the quality of the water once the hot tub is refilled.

How Often Should You Drain Your Hot Tub?

The water in your hot tub should be drained and refilled once its TDS reaches a level of 2500 (your local hot tub retailer can test your TDS level). While the exact timing of this will depend on your source water and how often it gets used, for most hot tubs this will mean draining the hot tub water every 3-4 months.

Read More: Hot Tub Maintenance Guide

How To Properly Drain and Refill Your Hot Tub

Step #1 – Preparation

Proper preparation will help you get the most out of replacing the water in your hot tub, while also making the experience smoother and easier.

The first thing you will want to do when preparing to drain your hot tub is to clean out the plumbing. To do this you will need a specialized plumbing cleaner like Ahh Some. Simply add the cleaner to the water and turn the jets on for around 30 minutes to allow the cleaner to fully flush out the plumbing. You will notice the water develop a thick coloured foam, this is completely normal.

While you’re waiting for the plumbing cleaner to do its job you can prepare the tools you’ll need to drain the hot tub. These tools are:

• A garden hose.
• A shop vac (not needed but helps).
• Paper towel or a cloth.
• A specialty cleaner for the hot tub shell and cover.

Step #2 – Draining Your Hot Tub

To drain the hot tub you must first turn off power to the hot tub. Once the power is off, attach your garden hose to your hot tub’s drain. Once your hose is attached, put the other end of the hose where you want the waste water to go and open the drain valve to start draining the hot tub.

Note: In some cities you are not able to drain your hot tub or pool into the street. Fortunately, low levels of chlorine or bromine won’t affect your grass and other plants in your garden. If you’re worried about your lawn, just test the water and ensure that the bromine levels are 10ppm or below (5ppm or below if using chlorine) before draining. If they are above that level, simply wait a day or two for the level to lower.

Once the hot tub stops draining, get your shop vac (if you have one) and remove the remainder of the water in the bottom of the hot tub. You can also put the end of the shop vac hose up to the jets and suctions to remove some of the remaining water in the plumbing.

Note: Gravity drains in hot tubs can take several hours to drain the hot tub and will often still leave a fairly significant amount of water in the hot tub. To make the draining process quicker and easier we recommend getting a submersible pump. These can be purchased relatively inexpensively and can drain fully drain a hot tub in a matter of minutes.

Step #3 – Cleaning The Surface Of The Hot Tub

When all of the visible water in the hot tub has been removed (there will always be a small amount in the plumbing that you won’t be able to remove), spray the shell and underside of the cover with a non-sudsing hot tub cleaner like Clean & Perfect and then remove it with some paper towel or a cloth.

Step #4 – Filling The Hot Tub

Once the hot tub surface has been cleaned, close the drain valve and remove your garden hose. You can then begin refilling the hot tub. When refilling your hot tub it is important to fill it from the filter area. This allows the pump to fill with water first and will prevent potential airlock issues when you turn the hot tub back on.

When the hot tub has been fully filled, turn the power back on and let the hot tub start to heat up. When the hot tub has heated to around 70 degrees Fahrenheit you can add in your startup chemicals.

Wrapping Up

While some hot tub owners dread having to drain and refill their hot tub, the truth is that it’s a fairly simple and straightforward procedure. Not only that, once you’ve got fresh water in your hot tub you’ll have a better, more natural bathing experience. You also may find that your chemical usage decreases with fresh water as the chemicals that you add will dissolve better in the water and your sanitizing chemicals will work more efficiently.