How to Keep My Black Water Tank From Freezing in My RV

How to Keep My Black Water Tank From Freezing in My RV
When RV camping in freezing temperatures, you not only want to keep yourself warm, you need to protect your black water tank from freezing. An RV black water tank that bursts due to freezing is a nightmare to deal with. Besides the expense of replacing the black water tank, the mess of sewage splattered everywhere is enough to make you cry. Some RVs are built with better insulation than others are, making the black water tank less prone, but not necessarily immune to freezing. No matter how your RV is built, by following a few steps you can winterize your black water tank to prevent it from freezing and becoming damaged.


Difficulty: Moderately Easy

Things You’ll Need:
  • RV antifreeze
  • Foam pipe insulation
Step 1
Empty the black water tank completely.
Step 2
Close the black water tank.
Step 3
Read your RV owner's manual to determine the size of your RV's black water holding tank, if you do not already know the size.
Step 4
Refer to the RV antifreeze instructions to determine how much antifreeze is recommended for your size black water tank.
Step 5
Turn off the water pump and disconnect the water supply going into your RV to prevent water from entering the black water tank, while winterizing the tank.
Step 6
Pour the recommended amount of RV antifreeze into the toilet. Hold the toilet's flush lever down while pouring the antifreeze so that it reaches the black water tank.
Step 7
Wrap foam pipe insulation around the black water tank dump valve as an extra layer of protection from freezing and to prevent the valve from freezing shut.
Step 8
Turn the water pump back on and reconnect the main water if you will be using your RV.
Step 9
Fill the toilet bowl with a little water as you normally would to keep sewage odors away, only if you are using the heater inside your RV. Otherwise, keep the toilet bowl empty.
Step 10
Keep the black water tank closed until it is 1/2 full, then empty it. Repeat the above steps to re-winterize your black water holding tank.

Tips & Warnings

Only use antifreeze designed for RVs. It is nontoxic so that it does not damage campground dump stations and will not harm your RV.

Article Written By Rose Kivi

Rose Kivi has been a writer for more than 10 years. She has a background in the nursing field, wildlife rehabilitation and habitat conservation. Kivi has authored educational textbooks, patient health care pamphlets, animal husbandry guides, outdoor survival manuals and was a contributing writer for two books in the Uncle John’s Bathroom Reader Series.

Don't Miss a Thing!

All our latest outdoor content delivered to your inbox once a week.



We promise to keep your email address safe and secure.