what to leave in black tank over winter

rrohrer · 10-07-2013, 10:10 AM

Over the yrs. after camping I have always left a gallon of water and some rv sewer treatment solution in my black tank after each trip. I was under the understanding that you shouldn't leave the tank completely dry. This would slosh around in there and keep the tank clean and maybe the seals not too dry? I've done it through the winter too, but last yr. I got freaked out thinking it could do damage when freezing. I'm not sure if that a risk or not since the tank is empty their would be room for expansion, but what if water down the pipe with little room to expand? So what is the best practice for winter storage? pour some pink down there?

Bugle Boy · 10-07-2013, 11:04 AM

I empty mine completely, clean the heck out of it and leave it empty with the cap off and the valve open.

Any water in the drain pipe could freeze and damage the pipe and/or valve.

Jim & DJ · 10-07-2013, 11:14 AM

I live in the northern part of Utah and the only thing I have done with the black tank is drain it and add 1/2 gallon or more of RV anti-freeze and have not had a problem within the last 7 years. Naturally, you must run RV anti-freeze through "any" water pipes until the water coming out of all faucets comes out pink, same with the flush valve and about a cup full in the pee traps. No pipe caps were left off..Good luck.

Have had Temps. in the single digit in years past.

My 1/2 gallon estimate is usually on an empty, or near empty tank or tanks.

Knock on wood.

Terrydactile · 10-07-2013, 11:50 AM

Just empty it and rinse it well. If you put anything in there for over the winter just pour a little RV antifreeze. The danger in what you are doing is that the liquid you are pouring in there could freeze against the valve.

**JRTJH** · 10-07-2013, 12:41 PM

Quote:

Originally Posted by Bugle Boy

I empty mine completely, clean the heck out of it and leave it empty with the cap off and the valve open.

Any water in the drain pipe could freeze and damage the pipe and/or valve.

X2 Water freezes and expands. Any water in a "confined space" such as the lines leading to the valve or the lines from the valve to the cap could freeze, expand and crack. Pouring antifreeze into the black tank will work, but my question would be, "How much antifreeze does it take to mix with the unknown amount of water in the tank so it will prevent freezing and expansion in the pipes?" So far, all I can come up with is a "best guess"... Using half a gallon or so may work for one person and be totally inadequate for another based on the amount of water left in his tank.

I also do the same for the gray water tanks.

So far, cleaning and leaving the valve and end cap open has worked for me too.

gepaine · 10-07-2013, 12:45 PM

After draining, I put one gallon of windshield washer solution in each waste tank. (It is about half the cost of RV anti-freeze.) I do not leave the cap off and valve open as I don't want any critters making a home in my tanks.

**JRTJH** · 10-07-2013, 12:58 PM

Quote:

Originally Posted by gepaine

After draining, I put one gallon of windshield washer solution in each waste tank. (It is about half the cost of RV anti-freeze.) I do not leave the cap off and valve open as I don't want any critters making a home in my tanks.

Please take a look at a previous forum thread regarding windshield washer fluid in holding tanks:
http://www.keystonerv.org/forums/sho...d+washer+fluid
Rather than repeat all of those points and counterpoints, it's easier to just refer you there, particularly post #19 with regard to evaporation and seal damage.

The alcohol in WW fluid will dry out the rubber seals in tank valves and will evaporate up the vent stack. If you cover your RV the petroleum distillates in the WW fluid could settle on your EPDM roof and cause problems. If you don't cover it and live in a climate where snow stays on your roof, the snow can act as a cover causing the same accumulation of distillates on the EPDM.

I'd urge you not to use WW fluid except possibly to clean the windows.

As for preventing critters from entering, you can use a piece of aluminum window screening and a 3" valve/hose adapter to hold it in place and prevent any mouse or chipmunk from getting into the system.

gepaine · 10-07-2013, 01:43 PM

JRTJH,

Thanks for the info regarding not using WW fluid in the waste tanks. I'm going to drain it out and add RV anti-freeze today.

**JRTJH** · 10-07-2013, 04:32 PM

No problem, Gene. I have been where you are more times than I care to admit LOL Sometimes we're our own "worst enemy." It seems when we try to "improvise and save" too often we wind up spending more than if we'd have done it the "tried and true" in the first place.

Here's hoping (and I'm sure they are) your seals in the dump valves are intact and in good condition.

campingcpl · 10-08-2013, 07:26 AM

I have always cleaned the tanks out completely before I winterize. I then blow out all the water lines and then pour roughly about a 1/2 to 3/4 of a gallon of antifreeze into each tank and make sure I get some into each pee trap. I then pour some into the toilet bowl to make sure to keep the seal from drying out. I've done this since the first trailer we have ever had and have never had any issues.

mikey98e · 10-08-2013, 09:59 AM

Quote:

Originally Posted by campingcpl

I have always cleaned the tanks out completely before I winterize. I then blow out all the water lines and then pour roughly about a 1/2 to 3/4 of a gallon of antifreeze into each tank and make sure I get some into each pee trap. I then pour some into the toilet bowl to make sure to keep the seal from drying out. I've done this since the first trailer we have ever had and have never had any issues.

I've done the same the past 20 years. Never put anti-freeze in the lines, just blow them out with air.
-mike

rrohrer · 10-08-2013, 06:42 PM

thanks everyone for your input.

theeyres · 10-08-2013, 08:01 PM

We've had various kinds of RVs for 40 years and lived in cold Eastern OR where it froze all winter. I just drained the tank and forgot about it. In all those years never had anything break or get damaged. I don't think you have to worry about. Only problem I ever had was when I forgot to pump the anti-freeze through the toilet and the intake valve froze and broke. Even that was a minor repair of one part. Don't create worries where there may not be any.

Justvisiting2day · 10-09-2013, 05:40 PM

We use ours all winter,, warm weather, but in the fall when we are off for a few months I drain completely and clean both tanks out as needed, leave open and make sure the fresh is cleaned also.

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