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Winterizing Part 4: Black & Gray Systems

| Updated Nov 23, 2021

This is Part 4 of our series on winterizing an RV. Part 1 covered draining the fresh water system, Part 2 was bypassing the water heater, and Part 3 was running antifreeze through all the fresh water lines.

Now that the fresh water system has been winterized with antifreeze, only a couple things remain.  If you did not dump your tanks prior to winterizing, now is the time to do it.  This year we added some laundry  soap (low suds), some beach, and some Calgon water softener to the tank along with a couple buckets of warm water to slosh around during the drive to the dump facility.  We did several extra rinses to leave the tanks as clean as possible for the winter.

Antifreeze in Sink  to fill trap
Pour anitifreeze in the sink to fill the trap.

You want to make sure you have antifreeze in the plumbing traps. That includes your sink (or sinks) and your shower drain.  The purpose of the trap is to trap some water in the line so no smells from the tank come out.  You don't want this water freezing and cracking your pipes.

Start by pouring antifreeze into the sink.  If you have a bathroom sink, pour some in it also.  About a cup will be enough, but extra will go into your gray water tank and mix with what little water still remains in it.

Antifreeze in Shower to fill trap
Antifreeze in the shower drain

Now pour antifreeze down your shower drain.  A cup should be enough.

Next pour some down the toilet.  There is no trap to fill, but you do want to add a little antifreeze to whatever liquid might remain in the black tank.

If – however – you have a macerator, you do want to get antifreeze into the macerator.  Like the city water input, it is easy to forget.  We have no personal experience with macerators, but we would guess you would want to put perhaps a 1/2 gallon of antifreeze down your toilet.  You would then run the macerator just long enough to see pink stuff.  If you have advice for those with macerators, please comment.

Remaining Antifreeze for flushing
Antifreeze for winter flushing

Now that you are completely winterized, you don't have to give up using your Roadtrek for the winter.  They are great winter camping vehicles.  Just make sure you have a full propane tank, you don't want to run out when its 12 degrees F outside (no we haven't done that, but we have been grateful to have a working furnace when it was 12 degrees).

In the winter we do not use our gray tank.  But we do use the black tank.  We just flush with antifreeze instead of water.  A cup or so is all you need.  The rectangular bottles of antifreeze fit nicely between the toilet and the wall and stay out of the way.

Water Container in Kitchen

For winter camping we put one of those RV dishpans in our sink (a perfect fit) and use the same drinking water container we use all year as the source of “running” water.

This rectangular container holds 1.25 gallons and it is held to the wall by two eyelets and a bungee cord.  We can disconnect the bungee (when parked) and rotate the container so the spout is over the sink.  This makes washing hands and brushing teeth easy.   If the weather isn't that cold we will dump the dish pan into the toilet.  If  it is cold enough that we don't want to further dilute the black tank we will dispose of  the dish pan contents elsewhere.

You are now winterized.  But don't let that stop you from winter travels.  With some Reflectix covering the windows, the propane furnace and/or electric heater will keep you snug.

Mike Wendland

Published on 2013-10-30

Mike Wendland is a multiple Emmy-award-winning Journalist, Podcaster, YouTuber, and Blogger, who has traveled with his wife, Jennifer, all over North America in an RV, sharing adventures and reviewing RV, Camping, Outdoor, Travel and Tech Gear for the past 12 years. They are leading industry experts in RV living and have written 18 travel books.

14 Responses to “Winterizing Part 4: Black & Gray Systems”

July 27, 2014at9:52 am, Karsten Askeland said:

Eric … When you winterize with the RV antifreeze the water lines get filled with the stuff.

Kathy … Last year it was soooo cold in my area that the RV anti freeze did start to crystallize some. Just kept an eye on it and kept an electric heater running inside during the coldest nights.

July 26, 2014at10:05 pm, Bill Long said:

My winterizing consists of heading south……

July 25, 2014at10:02 pm, Kathy Mullins Snider said:

this stuff suppose to turn to gel?

July 25, 2014at6:58 pm, Paul Konowalchuk Pogorzelski said:

Mike Wendland and/or RT Owners: when you winterize then decide to head out of town during the winter months, do you ‘de-winterized’ somewhere on the road if you’re heading south?

July 25, 2014at5:39 pm, Eric Buechner said:

Um, what about the water lines?

October 30, 2013at7:01 pm, Lynn & Roger Brucker said:

In response to Jim and Mary’s comments about what else we do for the winter. We are usually using our Roadtrek about once every 3 weeks over the winter, so we are not “storing” it. We do run the generator at least once a month at 1/2 load (electric heater in winter, A/C in summer). We do it for at least 30 minutes. Onan documents say 2 hours, Roadtrek says 1 hour, but the Onan Rep who came to the Branson Rally said you just need to bring everything up to stable operating temperature and if you are running under 1/2 load that will take about 20 minutes. It is more than running fresh gas through the carburetor. You want to dry everything out and keep those slip rings good and shiny (don’t ask how we know about that one). Moisture is your enemy with Onans. We now have solar so we haven’t had to plug in this year so far. But since we upgraded the old Magnatek converter (3 years ago) to a 3 stage charger we can leave it plugged in without trouble. We empty out food. Not just to avoid attracting mice, but also not to freeze cans of stuff. We clean out the fridge and leave it cracked open.

December 08, 2013at5:43 pm, Penrow said:

What do you mean you have solar? details? I realize I’m reading this late. Penrow. 11- 210 pop

December 08, 2013at6:51 pm, Lynn & Roger Brucker said:

Yes, we added a single 100 watt solar panel with a Morningstar Sunsaver MPPT controller. We only have a single 80 ah battery and our power use is likely below most Roadtrek owners (no inverter, LED lights, 12 volt TV and 12 volt computer / iPod / phone charging). We haven’t written about it here yet. That’s a topic for the future. There are a few more details about the system on this page:

October 30, 2013at6:30 pm, Mary said:

I also found this series very helpful thanks for all you do it has really helped speed up my learning curve.

October 30, 2013at6:12 pm, Mary said:

The only other thing I do is try and find premium ethanol free gas, and add a bit of Stabil or Seafoam for good measure. Then a run my generator for an hour or 2. I leave a good trickle charger on my engine battery (I have an isolater), and depending on sunlight (I have solar) I will sometimes plug in my RT. My RT doesn’t sit for that long.

October 30, 2013at9:53 am, Jennifer Fawcett said:

I don’t winterize as I pretty much camp year round here in Arizona; however, we can get some sub freezing nights. I keep reflectix in the windows while the van is parked, and before putting the cover on, I use a skirt made of tarps to go around the bottom of the van (held on by magnets). Those skirts come in handy on cold January nights as they help trap the earth’s heat and keep the camper a little warmer. I also prop open the fridge and under range cabinet to keep the warmer air circulating when I park the van.

October 30, 2013at9:30 am, Jim Diepenbruck said:

Lynn and Roger – thanks for the great four part report. Besides the fresh water system and the grey and black waster systems, do you have a list of other winterizing items?

October 30, 2013at9:18 am, Jonathan Clement said:

Thanks for this fine series regarding winterizing. It covers some items that the Roadtrek manual overlooks. I have printed it out for future reference. I am going to try to install a by-pass for the water heater next summer. Hopefully there is enough room behind the panel which covers the heater (and also holds the propane detector) to accommodate the by-pass.

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