Winterizing black and gray tanks

[lison]

Hi Folks. 'Been RVing for a dozen years in the freezing north, and never really worried about this, or seen anything written or found searching. Do you think the black and gray should be completely drained, or tank chemicals in as usual (plus whatever antifreeze gets in there from adding to P-traps)? Do you think it's good for the O-rings to dry out over winter if empty? I have done both. Have not had ever the outlet pipes freeze or break, but have had them start leaking, and replacing them was not a fun job. Would rather not have to do that again. Any advice appreciated. Thnx. -Luther
2017 Flagstaff Microlite
2009 Cherokee 5er

[CavemanCharlie]

I drain them completely then I add some pink antifreeze to them just to keep the seals on the drain valves lubricated.

[Grit_dog]

Dump ‘em. Run a little antifreeze down the drains to clear water out of P traps.
That is all.

[spoon059]

I don't want to leave anything in the black tank to dry and stick over the winter. For 11 years we've left a couple gallons of water (plus a little antifreeze from winterizing) in the black and gray tank. There is plenty of room for expansion in the tank, and it doesn't allow any residuals to dry in the tank.

I live in the mid-Atlantic, so winter lows rarely get into the single digits here.

[Beverley_Ken]

On my c-class I dump the tanks, close the valves and then winterize. what ever goes in the tanks (usually mixture of water pushed out and some pink). BUT I have no piping between the tanks and the valves. The valves are located on the side of the tanks and then the Y connector to the stinky slinky.
When I winterized my neighbours 5th wheel, I noticed that there was 5 to 8 feet of piping from the bottom of the tanks to the drain valves, in that case the pink is needed to keep the drain pipes from freezing.
Just depends of your unit.
Chemicals. Never used them, camping or storage.

Ken

[JIMNLIN]

I have a dump at home so nothing ever sits in my tanks very long. I open the drains and take the caps off and place piece of window screen over them to keep the critters out.

[kellem]

Plenty of room for expansion plus the residual of antifreeze during winterizing.
Those tanks pose no threat of freezing

[Mel_Stuplich]

Dick_B wrote:
I usually add one gallon of pink stuff to each tank after all of the other winterizing tasks are completed. It doesn't cost much and is cheap insurance. Valves closed of course.

I find that a quart in each waste tank is plenty.

[ksg5000]

Under ideal circumstances I would dump - but that's not life in my world. I put a jug of pink in both tanks and have had no issues for 20+ yrs. My black water tanks is mostly pee which is tough to freeze even without the pink stuff.

[Lwiddis]

I’m in the “drain ‘em and forget “em” camp.

[lison]

Thanks for the responses. That's what I was looking for. 'Have always done my own winterizing, and have read a thousand lists, made my own, and watched videos, but never seen anyone address the black and gray tanks.

[Dick_B]

I usually add one gallon of pink stuff to each tank after all of the other winterizing tasks are completed. It doesn't cost much and is cheap insurance. Valves closed of course.

[colliehauler]

I just leave the drains open to the dump station until I've completed winterizing. When done I close the valves and disconnect the hose. Anything that flows into the tank will be RV antifreeze. My seasonal has experienced -40 degree temperatures without any issues. I leave the faucets open as well for expansion.

[2oldman]

plenty of youtube videos on this