Hot Tub Care Hot Tub Maintenance

How to Drain a Hot Tub

How to Drain a Hot TubBy now, you have enjoyed the health, fun, and relaxing benefits of a hot tub. Right? As you might have noticed, hot tubs are somehow different from swimming pools. They need occasional draining and refilling. Doing this in a pool can be a considerable task which wastes too much water to be practical. But with hot tubs, it’s much feasible to drain, clean, and refill every few months.

Draining a hot tub is a crucial step to ensuring your unit is clean, balanced, and filled with some freshwater. And you know what? The process of draining, cleaning, and refilling is quite simple, but the process can be confusing at times.

Useful Tips to Drain Hot Tub

The good news is, my guide will help you drain your hot tub the right way. I aim to ensure any spa owner has an easy time while emptying, cleaning, and refilling his hot tub. I will detail how to drain a hot tub, how to clean after removing it, and how to refill it. So let’s get to it.

Why Do You Need To Drain The Hot Tub?

Can you imagine you sit on the same water for weeks or months? Think about it. Yes, you might be treating it using a sanitizer or shocking it regularly, but the fact is, this is the same water. At long last, you will need to change it, regardless of how vigilant and timely you’re with hot tub water maintenance. Every time you dip yourself inside a hot tub, you introduce new contaminants like the body oils, lotions, hair products, sweat, cosmetics, and more.

A human body carries some residue, and when you get inside a hot tub, they are all left there. The filters might catch the debris and leaves, but others will stick on the pipes while others pass past the filters. The contaminants and bacteria that build upon the plumbing start creating a biofilm layer.

But what’s A Biofilm?

A biofilm is a layer of bacteria and fungi which tracks down the water pipes. Due to the hot or water used in a hot tub, they feel it’s nice and cozy inside there, and they stick for a while. The sticking creates the right reproduction area inside the hot tub tubing.

However, since choline is a powerful enemy for the bacteria and the fungi, they form a barrier around themselves which is inaccessible even for chlorine. With time, more and more come along and join the family, while also digging in for a long time till the next draining and cleaning.

The longer the biofilm stays in your hot tubs plumbing system, the more the contaminants remain in the water, making it unsafe for you. When you allow them to build up for too long, the biofilm will start to interfere with the water flow and affect your hot tub filter also.

The worst is, you can do all the hot tub cleaning, but the buildup biofilm came along and ruined your work. Draining and thoroughly cleaning your hot tub as well as flashing the pipelines using active plumbing cleaning agent is the best way to get rid of the biofilm.

When Should You Drain your Hot Tub?

Often, this question hit hot tubs, especially when they learn it’s crucial to drain their units. But there are some ways you can tell your hot tub need draining, cleaning and refilling. Here are some few circumstances and signs to tell you when to remove it.

  1. One of the clear sign is when the hot tub starts giving off foul smell and odor. At this time, the water doesn’t clear, no matter what you try.
  2. Your hot tub requires draining, cleaning and refilling if you’re using it more frequently than usual. You might also be receiving more guest in the spa, often than usual.
  3. Lastly, you need to drain the hot tub if it has stayed unused for a long time or you intend to leave it unused for a long time.

How Frequently Should You Drain Your Hot Tub?

Aside from noticing the above signs or conditions to indicate your hot tub require your attention, you must drain and clean the hot tub every 3-4 months in a year, whether it needs it or not. Prevention is better than correction. Right?

By doing this, you will be preventing the biofilm from building up while also extending the life of the hot tub’s plumbing system and filter. The draining also maintains a cleaner and safer soaking environment.

For that reason, I suggest you always keep the instructions on how to drain a hot tub near you to make sure you follow the right steps every time.

How to Drain a Hot Tub

Before you can do anything, there are some things you need to do first. Draining is a series of actions to ensure you get rid of everything in the plumbing system. There is some work that you need to do before you can empty your hot tub.

1) Flush Those Lines

As I mentioned before, the gross biofilm can develop even if your hot tub sanitizer levels are always on point. The bacteria and fungi feed on it while also using it as a shelter guarding it against the sanitizer. With time the same bacteria ends up inside the hot tub. It eats up the chlorine and in the process exposing you to contaminants.

The contaminants can be dangerous to your health like the legionella, which causes the legionnaires disease, and the Staphylococcus Aureus responsible for causing hot tub folliculitis. There is also the E-coli that causes intense gastrointestinal distress. These are few of the many you can get.

After the biofilm forms inside the plumbing system, it cannot be removed with the average water circulation, sanitization, shock, or even filtration. That is why before you drain the hot tub, you have to add some plumbing cleaner or the so-called line flush product. The cleanser is designed to break down this biofilm for it to be flushed by the water.

While doing this, you must follow the package direction to use the right amount for your hot tub capacity. Once you have poured the solution, allow it to circulate the whole plumbing for around 20 minutes. However, if you have been cleaning the hot tub without using the plumbing cleaner, or the hot tub was unused for a long time, you have to give it some hours or even leave it overnight.

The whole process might produce a gross-looking foam on the water surface when circulating your hot tub. That shows its working, and it’s getting rid of the nasty biofilm. You don’t have to worry as the next step is the draining.

2) Turn Power Off

After flushing the lines, the next step is flipping the hot tub breaker to cut the power going to the hot tub to eliminate the electrical shock risk. You need to locate the circuit which controls your hot tub inside the household main circuit breaker board. Once you find it, turn it off.

3) Drain the hot tub

Typically, there are two ways you can drain the water inside your hot tub. You can either use its drainage system or use a pump to suck the water out. The machine will make the work much more comfortable and faster but will cost you electricity bill.

a) Using the drainage system

Connecting a hose to the hot tub drain and allow the water to flow is the low-cost option of draining the spa. However, you should know you need to be patient since it is time-consuming. It takes hours to have the entire hot tub empty.

It’s a good option if you’re not in a hurry. The method also gives you time to move the hose so that the drained water does not pool a single. It’s essential if you’re draining the water into the garden or yard. If it feels tedious, you can use a pump to suck the water out.

b) Using a Sump Pump

A sump pump is a water pumping device designed to help you get rid of flooded or stagnant water. With a sump pump, you can remove all the water inside your hot tub fast and efficiently. It makes the process go a lot faster, to be exact, in minutes. If you’re using the sump pump for the first time, you might want to stay near the hot tub to shut it off when all the water is emptied.

c) Drying the Hot Tub Using a Wet Vac

A wet/dry vacuum cleaner is an ideal device to remove any remaining water inside the hot tub. With a vac you dry the hot tub completely, removing even the dirt that might have remained after flushing the lines. It will also help you remove the water in the hidden areas like the around the seats and jets.

Where to Drain Hot Tub Water

Before you drain the water, you have to check your city’s law on water drainage to make sure you adhere to it and prevent damage to the environment. Different cities have laws which require you to drain your residential hot tub water into the sewer system. They provide sewer access using a drain linked to your property. Don’t confuse it with the standard storm drain which drains their water to natural water bodies.

For those with no direct access to the state, the sewer can run the hose into the standard utility sink drain in their home or use it to water their gardens or lawns. But you have to allow the chemical levels to dissipate first since plants do not thrive well on chlorine.

How to clean your hot tub

After all the flushing and draining, you now need to clean the whole hot tub to make it hygienic before refilling it. For you too it right you need to do the following steps.

1) Clean the Filters

Did you know you can easily remove the hot tub filters and clean them? Yes, you can when before draining, while draining or after. Cleaning them while you wait for the water to drain out is the best moment as it will help you pass the time.

For a complete and thorough filter cleaning, you need to use an excellent hot tub cleaning agent with a spray to loosen any stubborn grime, dirt, or debris on it. You then have to hose it off to force out the grime, dirt, and debris. You can also use some flush cleaners but check the label first.

For those filters that look particularly dirty, and it’s not long since you replaced them, you can soak them in a solution of vinegar and water or dishwasher detergent and water. The two are considered potent in cleaning. Soak the filters overnight and rinse them the next day with clean water.

Hot tub filters need replacement once in a year depending on the frequency of use. So, if it has been long since you replaced your, and they looked all junked up, you need to toss them away and replace with fresh new.

2) Clean the Hot Tub Interior, Shell, Jets, and the Cover

One of your hot tubs is empty, and you can now spray the interior, shell, jets, and the cover well with the appropriate hot tub cleaner. Allow it to loosen the dirt for about 5-10 minutes. Next, rinse the soap off using a hose to ensure no cleaning agent remains, then wipe it away using a soft absorbent towel.

Any cleaner residue left can change the water chemistry or even foam excessively. The amount of gunk left after flushing the lines and draining the water can give you a better idea of how dirty your unit is.

You can also use household cleaners such as Windex or even vinegar mixed with water. That depends on how it has been since you last cleaned it and the amount of buildup in the hot tub.

As I said before, try not to use excess cleaning agent, it will give you a hard time to clean, or affect the water chemistry after refill. You can even use a dry vacuum to remove the remaining cleaner from the hot tub bottom.

How to Refill a Hot Tub

You must set some time to attend the refilling. Not attending it might leave you with a flooding situation, mainly if it’s an indoor hot tub. Before adding the water to the hot tub, I suggest you check to make sure the circuit breaker is off for your safety.

Another thing, use a hose filter to minimize any impurities in the water such as copper and calcium. The contaminants can affect water chemistry and the overall hot tub health. Doing this will allow you to start with fresh, high-quality water and also reduce hot tub staining risk and any mineral deposit buildup.

Refilling and Sanitizing the Hot Tub

Now that you know what to do before refilling, it’s high time you draw near to reusing your hot tub. To start by inserting your hose into the filter section and turn on the spigot. That helps in forcing any trapped air out the circulation system thus preventing airlock in your hot tub.

You need to avoid overflowing since it can cause severe problems like backflow in the hot tub heater once you switch it on. If it happens to overfill, you need to drain any excess water right away.

The next step is to turn the hot tub breaker back on and start it. While at it, add the sanitizer and any other necessary chemicals. Remember to turn off the air valves, if your hot tub has them, to prevent them from disrupting the chemical distribution.

You can add the metal sequestrate if required. It’s crucial if you’re using well water or the city water with high metal content. It helps to prevent stains and mineral buildup, as the hose filler.

After performing the all above, next is testing the water. You need to adjust alkalinity, calcium hardness, and pH if necessary.

Next, cover the hot tub for at least 24-hours to let the water chemicals to circulate fully and your water to heat to around 80 degrees Fahrenheit, but not above 104 degrees Fahrenheit.

Once the water reaches the ideal temperature, you need to retest it to ensure it’s balanced before using the hot tub. Make the necessary adjustments if it’s not. You will need to repeat the step above, retest and balance it well if required.

If your hot tub uses a saltwater system as a sanitizer, I suggest you wait until the water chemistry is wholly balanced before adding the salt and turning it on. You need to achieve the right PH and alkalinity before starting the production of chlorine.

Having done all that, you can add any other things to spice up the relaxation like the aromatherapy crystals or liquid.


Now you have 3-4 months to repeat all these. It might seem to be a long process, but everything is a ‘Do It Yourself’ steps. There is no need to pay somebody to do it. But if you have a busy schedule, you can find the right person for the job. Now that you know everything you need to keep your hot tub clean, safe and healthy, you don’t have any excuse to have unclear water.

About the author

Sharif Miah

Hi! I'm Sharif, the founder of Globo Pool® and I have been working in the pool & hot tub industry for the last few years. I love to share my experiences with people & hope you are enjoying my information and lessons!

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