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How to Use Rock Salt to Keep Blackwater Tanks From Freezing

Black water tanks in travel trailers and RV's, which store organic waste from toilets, require winterizing during freezing temperatures. Winterizing a black water tank reduces the likelihood of failure during use during freezing temperatures or while being stored. Failure is typically caused when the moisture in the tank freezes and expands which creates cracks in the tank or tank seals. Winterizing a black water tank during freezing temperatures ensure long years of service.

Rock salt
Fresh water

Instructions

- 1
  Connect a dump hose to the dump system, and open the black water dump valve to drain the black tank. Close the valve when the dumping process is complete.
- 2
  Add 3 pounds of salt to each gallon of water to be added to the black water tank. Typically, 1 to 2 gallons of water is used to winterize the tank. Ensure that all the salt is dissolved in the water, before you add the saltwater to the black water tank.
- 3
  Add 1 to 2 gallons of salt-saturated water to the black water tank. Salt saturated water will lower the freezing point to approximately -6 degrees Fahrenheit (-21 degrees Celsius).
- 4
  Add other chemicals required for black water tank maintenance. Aqua Kem, Camco, Exodor and QT RV Tank Treatment all provide products that deodorize, breakdown waste and reduce solids.