How Do I Unfreeze My RV's Grey Water Tank?

by Garry
(calgary)

Help our gray water tank has frozen what can I do?

ANSWER: Greetings Garry thanks for submitting your question on our Ask An RV Question Page.

You do not tell me how full your Grey Water Tank is. If your Grey Water Holding Tank is completely full Option 1 may not work, but still give it a shot then skip to option 2.

Option 1 Partially Filled Grey or Black Water Holding Tank

You will need at least 3 gallons of RV Holding Tank Antifreeze. Start by pouring a 1/2 gallon of antifreeze down the bathroom sink drain, the shower drain and the kitchen sink drain. Once you have done that you need to pour about 1/2 gallon of boiling water down each of the three drains mentioned above. Then again pour another 1/2 gallon of RV Holding Tank Antifreeze down each of the drains.

If you have a motorhome, you may want to drive it around for at least 30 minutes to circulate the antifreeze inside the holding tank. If you have a trailer; or if it is not possible to drive the motorhome let the antifreeze sit in the holding tank for at least two hours, before attempting to dump the tank.

Special Note If Holding Tank Dump Valve is frozen You can use a Hair Dryer on high setting to melt ice and free up the dump valve. Once the tank has been dumped, you need to Winterize Your RV.

Option 2 for a completely full holding tank

You need to get as much RV Holding Tank Antifreeze into the holding tank as you can. You will know that the tank is completely full when the antifreeze starts backing up into your shower. You also need to get as much heat as you can into the frozen holding tank.

In some RV's there are furnace vents that run into the holding tank compartments if your RV has one of these setups you may need to crank up the furnace to a higher than normal temperature to melt some of the ice and allow the antifreeze to start working.

If you have a heat lamp available to you and you can "safely" place it near the grey water holding tank, it may provide enough heat to get the tank warm enough for the antifreeze to start doing its job and get things flowing again.

There are also Holding Tank Heater Blankets available that can attach to your holding tanks to warm them up and keep them from freezing.

I hope that this information has been helpful to you.

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Happy RVing

RVing Al