# Black water holding tank in freezing temps



## prichardson11

We're having to stay in the rv during the winter for at least half of the time while we work on a project out in the sticks. The last couple of weeks have been freezing weather (even in Texas!) and we needed to dump the black water. Well, it was frozen...not a pretty sight. Major amounts of running water through the system got maybe half of it out. Is there some form of antifreeze solution that can be added to the tank while still in use? We can't winterize for storage since it will be in use. Any ideas? Thanks to all.


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## ctfortner

I have heard of others adding rv antifreeze into a frozen holding tank to get things moving. I have also heard of using a heat lamp and placing that close to the tank, but not touching. Just to provide some heat and possible thawing. One other thing you could try would be boiling or hot water added to the tank to thaw it enough to drain it all out. 

As for keeping it thawed, they do sell holding tank blankets, you may want to look into that for using the camper throughout the winter.


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## frank-id

*Add salt to the tank*

Any type of salt will allow the tank contents to melt. The salt will not affect the tank. Do not allow tank to become full of waste. Frank


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## reinreb

All good ideas but keep in mind salt water freezes at 28 deg F. Make sure you don't put the heat lamp too close to the plastic holding tank. If you wrap some kind of skirt around the trailer base (tarp or cardboard) it will greatly reduce the circulating cold air that is causing the problem. Using any kind of heating device would be more efficient this way. If I had the problem though, I would use plenty of RV antifreeze mixed into the tank. Good luck. 

freezing in Texas????


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## artmart

I have heard others from other forums about this problem and some of them have put very hot water in the tanks just to get more effluent going. Just make sure that you evacuate as much of it as possible because hot water loses its heat and will freeze pretty quick, but hopefully it will be down the drain and out of your plumbing before that happens.

Can anyone else confirm or add to this?


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## dogbone

I, myself wouldn't use salt. It will stick together and form a blockage in your tanks. It will be tough to get it out. Especially rock salt.
Do what you can to get the stuff out. Hot water, probably the best. If and when you get it cleaned out and heating the tank is not an option, flush using windshield washer fluid. It is the cheapest antifreeze and good down to 20 below. If there is any ice left, it will tend to melt it also.


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## Redguitar

The tank itself does not appear to be frozen, I just know I cannot get the knife/dump handle to operate. Have tried hair dryer but have not tried the RV anti-freeze, but after reading this, that is the next order of business ~
Thank you, I will keep you posted.
Red


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## frank-id

*Holding tanks can be used with care..*

My earlier post will work OK if the waste is still a liquid. After any holding tank is frozen solid other methods must be used. I have used a barbeque with no legs, and placed same under a tank that is solid. After a lot of time and brickettes, the ice block will begin to melt. Then the discharge valve can be tried to drain some liquid. Once the frozen ice is less volumn, warm ice melter can be used. To speed any ice melting, the ice melter is added to some RV antifreeze, that is heated and not boiling. Here in Idaho, the temps have been in the -10 degrees. My septic system was slowly becoming restricted. So a quart of disolved ice melter was added to toilet today. The drain seems to be working OK.... Frank-id...................Twin Falls 2016


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## cridhe_fior64

I've been using the RV Antifreeze. Am I NOT supposed to use it to keep it flowing correctly?

Patti


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## frank-id

*Any antifreeze is OK*

Some folks also use lots of salt. It is cheap and available every place. Water softening salt is the cheap stuff. Check the drain valve to check for liquid.
Create some hot water and add salt, when dissolved add to the black holding tank. Spring is coming but maybe not tomorrow.. Frank


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## saphiro

Stay safe then, Happy new year!

-Chad
floor coating contractor wilmington nc


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