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What is the Black Stuff Coming Out of My Hot Tub Jets?

By October 21, 2020August 4th, 2021Home Maintenance
What is the black stuff coming out of my jacuzzi jets

Many homes have a hot tub, which is a bathtub with jets. It is usually found in the master bath.  Often, it is also referred to as a whirlpool.  Hot tubs are nice and relaxing and can help after a rough day or a migraine. 

Imagine getting into your hot tub to relax from the tough day and there is black stuff coming out of the jets!  It may have you wondering, what is the black stuff coming out of my hot tub jets?  Well, it is mold, mildew, soaps, bacteria, oils, and other stuff. 

Unfortunately, the hot tub can be a breeding ground for bacteria and other things. Let’s take a look at what the black stuff is coming out of the hot tub jets, how to prevent it, how to clean the hot tub, and information about bio cleaners so this doesn’t happen to you again.

How to Prevent the Black Stuff from Coming Out of the Hot Tub Jets

Prevention is key in keeping the hot tub clean.  It should be cleaned before and after each use.  Many people don’t think about cleaning it before using it, as they just want to get in to relax from the day.  However, it is important to do so, if possible. 

If that is too much to do, then make a plan to clean it every month.  Try to do it before the black and brown flakes start to form. These baths have a hard time draining so they don’t get as clean as a regular tub.  They stay warm and damp inside the pipes so they create a breeding ground for bacteria and biofilm.

How to prevent the black stuff from coming out of the hot tub jets
Moisturizers can cause build up in the pipes

Oils and emollients (products that contain moisturizers) can cause the build-up very quickly as they are difficult to get through the pipes and leave a residue.  A good idea is to use oil-free products and bath salts and this should help.

How to Clean the Hot tub Jets

The good news is that it doesn’t take long to clean a ho tub. Follow these steps below and you should be on your way to a cleaner hot tub.  If not, contact a professional to take a look at the system.

1.Fill the tub with hot water

Filling the tub with hot water and making sure it is at least two inches above the highest jet is important.  This will allow the water to get into the jets and start loosening up the gunk.

Next, add a half-gallon of distilled white vinegar.  White vinegar is a great cleaner, as it is acidic and can counteract yucky buildups.

2.Turn off the air valve (if there is one)

If there is an air valve, run the jets for at least 15 minutes.  This allows the vinegar water to act as a cleaner and clean out the gunk from the pipes and walls of the jet.  Next, let the water sit for 10 minutes.

3. Drain the tub and then refill

Drain the tub and then refill it with cold running water for 10 minutes.  This will allow the vinegar to get out of the tub and the tub to be cleaned.

How to clean the hot tub jets
Clean Hot Tub

4. Drain the tub and wipe it down

Drain the tub and wipe it down with a soft cloth.  Your hot tub should be nice and sparkly!  Plan on a calendar when you will clean it again so you don’t forget.

Bio Cleaners Can Clean the Black Flakes Too

If you don’t like using white vinegar or maybe there is an allergy, try a bio cleaner.  A bio cleaner is a cleaner that is good for the environment, non-toxic, and can get rid of the bacteria, dead skin, mold, and other gunk in the hot tub and remove it from the piping.


Hot tubs are wonderful and relaxing and with proper maintenance, can last a long time.  Thankfully, it is not difficult to clean but does take some preparation.  If you are having issues with the jets in your hot tub, let us know and we can inspect them and help diagnose the problem.

Do you have other ways to clean the hot tub or have you used bio cleaners?  Leave us a reply below and let us know your thoughts!