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How to Clean Hot Tub Plumbing

By Matt Giovanisci | Updated: May 28, 2016

You may spend countless hours carefully managing your hot tub’s water, but that doesn’t mean that you ever think much about the plumbing. Over time, your hot tub’s plumbing can become coated with slime, sludge, and grime that can contaminate your water supply and even make you sick!

It is important to periodically perform a hot tub line flush if you want to make sure your water quality is always at its best. But pipes aren’t as easy to get to as the water and shell of your hot tub. So how do you do it?

Why Do a Hot Tub Line Flush?

You may be thinking that with all the chemicals you pour into your hot tub, a good line flush just seems unnecessary. However, over time even when you properly take care of your hot tub, the plumbing inside your hot tub can begin to accumulate mineral deposits, dirt, grime and much more inside them that normal chlorine simply can’t take care of on its own.

A hot tub line flush will get rid of this buildup so your water stays as clean as it possibly can.

How Often to Flush Hot Tub Lines

So how often should you flush the pipes? A good rule of thumb to go by is whenever you drain the hot tub, flush the plumbing as well. Depending on your hot tub use, you should drain and clean it once every 3 months. More often if you use your hot tub frequently.

Signs That It’s Time for a Cleaning

So how do you tell if it’s time for a good cleaning of your hot tub plumbing? If you notice slime forming in your water or if the water is cloudy and you smell musty odors, it could be time to flush out your system.

Another more serious warning sign is skin rash. If you get a rash on your skin a few days after using your hot tub, it is definitely time to give it a good cleaning.

Clean Your Hot Tub’s Plumbing

While you may regularly take steps to treat the water in your hot tub, periodically you need to give your hot tub’s plumbing a little tender love and care as well. When cleaning your hot tub’s plumbing, there are a few steps you need to take to be sure it gets cleaned the right way.

Clean or Replace the Filter

Remove the filter from your hot tub and clean it. If it is a year old or more or if it looks like it is in bad condition, replace it. Consult with the manual for your hot tub to be sure you purchase the correct filter for your hot tub.

Note: Leave the filter out during the flushing process.

Shock Your Hot Tub

While you will be changing the water, you need a decent base to start your cleaning process. So, using the water that is in the hot tub, add shock and allow it to circulate through your hot tub and clean as much of the water killing any bacteria that may be present in the process.

Circulate the water at high speed during this process and allow it to run for at least 30 minutes, if not longer before you continue.

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Flush the Plumbing System

Next, add a hot tub line flush product to clear the biofilm from the pipes, turn the jets on high, and allow the water to circulate for 15 to 30 minutes. This system flush will break up much of the sludge and grime that has built up inside the pipes of your hot tub and allow it to become trapped in the filter.

Once the water has circulated, turn the hot tub off, cover it, and let it sit for at least 5 hours. You can also do this in the evening and let it sit overnight if that’s more convenient.

Important: While there’s nothing wrong with using vinegar to clean a hot tub, it’s not the best choice for cleaning hot tub plumbing. The sludge that builds up in the pipes responds much better to a hot tub line flush that will break it down so it can be washed away. We highly recommend sticking with that to make sure the pipes are clean and clear.

Drain the Hot Tub

There’s no way to completely remove the hot tub line flush product without removing the water. If you’ve never done it before, take a little time to learn how to drain a hot tub to ensure you do it correctly.

Clean the Hot Tub

Take advantage of the spa being empty to really give it a good, thorough cleaning. Wipe it down with diluted white vinegar, or use a special hot tub cleaner formulated for removing accumulated nasties from spa surfaces.

No matter what you use to scrub your hot tub, be sure to rinse it thoroughly before you start refilling, or you may end up with a bubble bath.

Refill the Hot Tub

Put the filter back into your hot tub, then refill the tub with fresh water. Use a hose filter to keep as many contaminants out as possible.

Once the hot tub is filled, test the water and add the proper chemicals to balance it properly and allow the water to circulate through the hot tub for at least 8 to 12 hours.

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Verify Your Results

After your hot tub has circulated, retest the water and consider shocking the new water to ensure that you have removed any dirt, grime and bacteria from the hot tub.

If you do shock the hot tub, you’ll need to test the water again and be sure it’s properly balanced before you use it.

When All Else Fails

Sometimes, the pipes will simply be too gunked up with grime, dirt and all manner of nastiness that you just can’t take care of it with a simple hot tub line flush. When this happens, you need to either put your plumber hat on or call in a professional.

Either you or the professional can disassemble the plumbing properly and clean the pipes by hand in order to completely remove all that dirt and grime that has built up inside the plumbing of your hot tub.

Flush Away!

As they say, it’s what inside that truly counts, and the same goes for your hot tub. No matter how clean the outside and the shell of your hot tub is, if the plumbing is dirty, your water quality will suffer.

Doing a hot tub line flush doesn’t have to be difficult, if you do it regularly, you’ll quickly be able to enjoy your hot tub a lot more knowing the water you’re soaking in is truly clean.

Happy Soaking!

Matt Giovanisci is the founder of Swim University® and has been in the pool and spa industry since 1995. Since then, his mission is to make pool and hot tub care easy for everyone. And each year, he continues to help more people with water chemistry, cleaning, and troubleshooting.
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