How Often Should You Change Your Hot Tub Water?

How often should you change your hot tub water depends on the level of usage of your hot tub and the water chemistry.

When you follow your hot tub maintenance schedule and maintain correct water chemistry I recommend to change the water every quarter (3 months). I recommend starting each season with a clean hot tub, new filter element and fresh water. However, if the hot tub water become dirty or contaminated the water must be replaced.

How often do you have to change the water in a hot tub?

The frequency that you change the water depends on the level of usage of the hot tub. Usually, I recommend to change the water every quarter (3 months). If you are not using the tub at all then there is less need to change the water. You could let it go for 6 months.

When the hot tub has high usage from many people the water will quickly become contaminated with sweat, skin flakes, hair, body oil and many other substances. The only way to properly sanitize a hot tub is to add more chlorine or bromine. After a while the small volume of water in a hot tub becomes too dirty and contaminated to sanitize with chemicals. The only option to clean the water is to drain and refill the hot tub.

Please read our article on Should I Winterize My Hot Tub?

How often should you clean a hot tub?

I recommend draining and refilling a hot tub 4 times a year. While the hot tub is empty you must clean it before refilling. Yes, you must wipe down the inside surfaces of the hot tub but the most important part to clean is the plumbing and filter. Most of the dirt and contaminants hide in the pipes and filter. Flush the pipes with a hose and clean or change the filter cartridge.

How to Empty a Hot Tub for Cleaning

Where do you drain the water in a hot tub?

Many hot tubs have a drain plug at the bottom external wall of the tub. Open the plug to drain the water. Some allow a hose to be attached before opening a valve.

If your hot tub does not have a drain plug or valve you can either siphon out the water or use a submersible water pump.

The water can be directed into a stormwater drain or on to a lawn or garden.

What is the best thing to clean a hot tub with?

There are many hot tub cleaners available on the market. Do not use harsh cleaners as they may damage the surface. These cleaners may leave chemical residue that causes foaming in the water when you refill the tub. Only use weaker spray-and-wipe style cleaning products. Some people use Windex glass cleaner as it is gentle on hot tub surfaces.

When your tub is fill of water try to prevent waterline marks appearing by regularly cleaning around the waterline with a cloth and spray-and-wipe cleaner.

When Should I Shock my Hot Tub?

If you are using your hot tub shock it once a week. Don’t use the hot tub until the next day as the chlorine level will be too high for bathing after shock treating the water. You don’t need to add much shock to a hot tub. Many people add too much shock to their hot tub and make the water cloudy. A hot tub only has a small volume of water not like a swimming pool. Please follow the manufacturer’s instructions for the correct amount of shock for your size hot tub.

How long after you shock a hot tub can you get in?

When you shock a tub with chlorine-based shock you need to wait until the next day before it is safe to use the hot tub. The chlorine level must be below 5ppm otherwise it will irritate your skin, lungs and eyes.

When you shock a hot tub with non-chlorine based shock run the pump and circulate the water for 20 minutes before getting in the water. Non-chlorine based shock is less effective and reactive than chlorine but much gentler on your skin and eyes.

Can you over shock a hot tub?

Yes you can. Always read the instructions on the container or packet before adding shock chemicals to a hot tub. Only add a very small amount of shock. If you have added too little you can always add more. But if you add too much you will need to wait several days for the chlorine level to reduce to below 5ppm before you can safely get in the water.

Should I leave my hot tub filter on all the time?

Yes, I recommend you leave the filter on all the time to keep the water clean and circulated. Once the water becomes dirty or unsanitized you need to change the water. The filtration system operates on a timer to clean the water for the correct amount of time each day. Many people don’t realize that it’s more economical to keep the water warm than to heat it from cold each time you want to use the tub. Keep the lid on the tub to preserve the heat and keep out dirt.

Can too much chlorine make hot tub cloudy?

Yes, adding too much chlorine too quickly is a common mistake people make with their hot tub. The water will be supersaturated with chlorine causing the water to look cloudy. Always add sanitizing chemicals in small amounts with the pump running to circulate the chemical through the water and plumbing. Check the chlorine/bromine level with a test strip until you have the desired level.

If you have added too much chlorine or bromine wait a few days for the sanitizer to be consumed and the level will return back to normal.

How often should you change the water in an inflatable hot tub?

I recommend changing the water in an inflatable hot tub at least every month when the tub is frequently used. Maybe every 6 to 8 weeks when used less frequently. Inflatable hot tubs don’t hold a lot of water so it’s not an inconvenience to change the water frequently. I believe it’s better to change the water rather than use more chemicals to sanitize the existing water. Once the water begins to look cloudy or green it’s time to change it.

Should I leave my inflatable hot tub on all the time?

I recommend leaving on your inflatable hot tubs all the time to keep the water circulated and ready for use. You cannot leave a hot tub full of water without circulating the water and sanitizing it with chlorine or bromine. The water would quickly become stagnant, full of algae and turn green.

If you don’t plan using the hot tub more than a couple of times in a month you should empty it and refill when you do use it. Leaving a hot tub on for weeks while not using it is a waste of energy and will cost you money.

How long can water stay in an inflatable hot tub?

Water can sit in an inflatable hot tub for up to half a day without sanitation chemicals. After that the water will become unsanitary with bacteria and algae growth.

If you are only planning to use an inflatable hot tub for the day it’s safe to not use chlorine or bromine. Remember the water will take up to half a day to heat from cold.

After one day you will need to add chlorine or bromine to the tub to prevent the growth of bacteria and other contaminants. The hot tub water must be filtered through the pump every day to remove dirt and dead contaminants from the water.

How Do You Siphon Water out of a Hot Tub?

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How long does a hot tub take to drain?

This depends on the method of draining and whether there is a drain plug or not. A drain plug or a submersible pump will drain a hot tub in 10 minutes. Siphoning a hot tub by gravity may take 30 minutes or more depending on the height difference between the two ends of the hose.

Is it safe to drain hot tub water on grass?

You can drain your hot tub water onto your lawn and garden. The water is balanced with neutral pH and low levels of chlorine or bromine. The water will not damage plants or grass. If you have a saltwater spa it is fine to drain the water on to the lawn as the salinity level is very low. I recommend you spread the water around and do not drain it all in one place. Hot tubs can hold up to 1000 litres of water so you don’t want to wash away the lawn or plants.

Can you water plants with hot tub water?

Yes, you can water the garden with hot tub water. The water has balanced pH and low levels of chemicals which will not harm the plants. Some people siphon the water from their hot tub on to the garden but move the water around as there is a lot of water in a hot tub.

Can I drain my hot tub into my pool?

If you hot tub water is clean and sanitized there is no reason why you cannot drain the water into the swimming pool. The chemicals in the hot tub will help maintain the water chemistry of the pool.

Many spa pools are built to overflow into a swimming pool. It’s normal to empty spa water into a swimming pool.

Conclusion

Hot tubs contain a relatively small body of water that can quickly become contaminated even with sanitation chemicals.

I recommend changing the water in a hot tub every season when the tub is being actively used. It just makes more sense to empty the water, clean and refill rather than load up the hot tub with extra chemicals to keep it clean. I also recommend to start the season with a new filter cartridge.

Please check out our other posts on how to care for a hot tub.