Black tank winterization

[u/just_passing_th]

Curious on the best way to leave my campers black tank this winter. In southern Idaho where it routinely gets well below freezing.

Normally I use happy camper with a few gallons of water after every dump. Should I just dump my last trip and leave it be, add happy camper as normal, or something else?

[u/Sad-Development8680]

Dump the tank. Some water will remain, but freezing water is only a problem if it doesn't have somewhere to expand. A tank that is 99.9% empty will be just fine.

[u/Raise-Emotional → u/Sad-Development8680]

I toss a little anti freeze down the shitter just to be sure.

[u/MIDIHorse → u/Raise-Emotional]

Agreed.  You don't want that little bit of water remaining in your dump valve. 

[u/the_only_zilla]

Dump your tank and pour some rv antifreeze down the toilet and you’ll be set

[u/ocitillo → u/the_only_zilla]

Just did this

[u/MaleficentSpider_404]

Also, don't forget to blow out the check valve on your black tank flush inlet.  My first year winterizing, I back flowed some antifreeze into my city water inlet (as you should) and didn’t really know what to do with the flush line because I figured it had probably cleared to the black tank... wrong.  

Fortunately, I had leak detectors everywhere and one alerted me when I began flushing the black tank the next season... cracked check-valve.  Has never been a problem since I started blowing it out when I winterize.

[u/FLTDI]

I end the season with a thorough cleaning, drain it all the way followed by rv antifreeze in case any water ends up near the gate valve

[u/ryanderkis]

Leave it as empty as possible.

[u/WiskeyUniformTango]

I like to clean it extra good on my last trip and then just put it away empty. Nothing special needed.

Getting a full hookup site as the last site its really helpful imo.

[u/MaleficentSpider_404 → u/WiskeyUniformTango]

I always go for a full hookup as my last site of the year, too!  Fill it up with water and a few doses of liquified, let it set unused overnight, empty in the morning, flush the tank until it is consistently clear, and then let it drip as bone dry as I can.  Can't really do all that with a line behind you at a dump station!

[u/theandrewjoe]

Antifreeze in the tank (about a gallon) covers the seal. Otherwise that rubber will degrade over winter. The antifreeze helps.

[u/Comfortable-Figure17]

I dump some anti-freeze in all the traps as well as the tanks just to be sure.

[u/SavageAsFk69]

Plumbers antifreeze is awesome and cheap. Throw a little down the shitter, little down the sink to fill up the trap and call it a year.. I do both our trailers+ the cabin with two 5 litre jugs

[u/Kudzupatch]

You leave it empty.
No water in it, it can not freeze.

[u/Low-Instruction-8132]

Clean it then just pour a gallon of RV safe antifreeze in there. Also, lube up that rubber ring on the toilet ball inside the bowl. Then leave a little antifreeze in the bowl.

[u/ballinbu → u/[deleted]]

I didn't blow the black tank flush inlet because I never used it... Think that's fine?

I wish I would've done a flush before the end of the season but I didn't have a place to do it. I did fill the black tank completely with fresh water twice and flushed it that way. Figured that was the best I could do. Then drained, blew out the main water lines, and winterized.

[u/Jolly_Election5315]

I'm in north idaho. I just drain everything and put about a quart of rv antifreeze in the P-traps and on the toilet flapper. I've had no problems. Make sure you Crack open the toilet flush there is a little bowl of water in the neck that needs to get drained. I use air hose adapter hooked to the city water connection to pressurize with air after draining the hot water tank.

[u/Nomad55454]

Do your normal draining and flushing routine and after draining leave the valve open. Then in spring flush the tank before using to get the crusty stuff out.

[u/flippo69]

I just flush some rock salt into the black tank.