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lordnorth's avatar
lordnorth
Explorer
Nov 10, 2014

Winterizing: Holding tanks dry or not?

I am sure this has been addressed to death, but I have done a search and can't find the answer.

I am doing my first winterization (Pennsylvania) and I don't know if I should completely DRAIN my holding tanks - leaving the dump valve open, Complete FILL the tanks (this is what the anti-freeze bottle suggests), or trying to leave a little bit of anti-freeze in the tanks with the valve closed.

Seems to me it would make the most sense in terms of freezing to open the drain valve to avoid any potential damage... but instructions tell you never to let the black tank dry out.

Can anyone give me some advice?

Thanks!
Chris
Seeking Advice

22 Replies

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  • DutchmenSport's avatar
    DutchmenSport
    Explorer
    Nov 10, 2014
    I drain the holding tanks until absolutely nothing drips any more. Then pump the pink through the sinks and toilet and down the tanks. I make sure there's just enough to keep the dump valve knife blade seals wet with pink. And actually, you could dump that little bit too. The droplets that stay on the seal won't hurt anything.

    Any drop of water will expand. Even the tiniest drop will expand. The question is, the space it has to expand, is it bigger than the expansion or smaller? If smaller you want to displace it with pink or make sure it's 100% dry. Open or closed, I don't think it matters, provided all the water is gone.
  • donn0128's avatar
    donn0128
    Explorer II
    Nov 10, 2014
    Dump the tanks, close the valves and your good to go. Be sure to add antifreeze to the toilet bowl and sink "P" traps

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