Saturday, December 9, 2023


What kind of RV antifreeze should you use?

The leaves are changing color. Squirrels have stepped up their nut-hiding pace. Yep, winter is decidedly on the way, and if you’ll be letting your rig sleep for the winter, you’d best take good care to winterize your plumbing system. What kind of RV antifreeze should you use? What? You didn’t know there were different types?

Two kinds of different ingredients

No, we’re not talking about RV antifreeze versus automotive engine antifreeze. The latter is really toxic—pump it into your RV plumbing system and you’ll have serious, if not deadly, regrets. RV antifreeze is designed for potable water systems. It’s not toxic, although we’d avoid mixing with 7-Up for a highball. We’ve heard the taste is a bit on the unpalatable side.

So what kind of RV antifreeze should you use? It comes down to the basic working ingredient. Some folks will just walk into the RV supply store and ask for a couple of gallons of “the pink stuff.” Now, maybe that could be mixed with some whole cream…

Alcoholic antifreeze?

Yes, we’ve been dwelling a bit on alcohol in the last couple of paragraphs. Some types of RV antifreeze do indeed contain alcohol. What sort? The somewhat non-toxic ethanol variety, grain alcohol. When ethanol “mixes it up” with water, the result is a lowering of the freezing point of water. That’s great for keeping the water from going solid, and expanding, and breaking your pipes. But there’s another contender in the RV antifreeze market.

That “other” active ingredient is technically a “double alcohol”—propylene glycol. It, like its competitor, ethanol, does its job by lowering water’s freeze point. Essentially the two different types do the same job. So what RV antifreeze should you use? We hear it coming: “If they both do the same job, use the one that’s cheaper!” Our bank account applauds you, but there’s more to the story.

One could leave a bad taste in your mouth

While ethanol-based RV antifreeze could technically be cheaper, come next spring, it could leave you with a bad taste in your mouth—literally. We’ve had RVers report that they used the cheap-o ethanol brands, but even after repeated flushing, found the taste left over in their water system was gaggy. Even if you just use your RV water for cleaning and toilet flushing, beware of two other possibilities. Reports show up that rubber seals can be adversely affected by contact with ethanol: Read that, “leaking.” And finally, ethanol fumes are flammable, so use it with care around flame or heat. Shut down motors and pilot lights when using the stuff.

And a virgin in the mix

So, boiling it all down, what RV antifreeze should you use? Is it “all for propylene glycol”? One manufacturer who made a brand of RV antifreeze based on propylene glycol touted its own product. It also warned against how some competing brands might use “recycled” products. Imagine RVers running out with buckets every spring, catching those precious drops of antifreeze, and shipping them back to some chemical plant for recycling! NOT! Rather, last winter (or earlier), when airplanes sat on the tarmac in a snowstorm, how did field crews keep them from icing up? They sprayed them with aircraft antifreeze, made with, of course, propylene glycol. Rather than letting that antifreeze go, some airports ship the used product back to a recycler. That, said the manufacturer, could lead to all sorts of nasties in RV antifreeze.

We tried to track down more information about this. Some “RV websites” tout various brands that supposedly contain “virgin” propylene glycol (PG). Maybe yes, maybe no. Some claimed Walmart’s SuperTech RV and Marine antifreeze was 100% virgin. A quick look at the product’s safety sheet positively states it does contain propylene glycol—but no statement as to how “pure” that is. But that same product ALSO contains ethyl alcohol! Look as we might, we could find only ONE RV antifreeze that actually claimed to use 100% virgin PG. That’s the Star Brite brand, but sadly, it doesn’t appear to be widely distributed.

Does it matter? We’re not quite sure. The company that ballyhooed its virgin purity didn’t explain in any great detail as to what might be in recycled PG that was so awful.

Here’s what some brands contain

Here’s a chart showing some brands of RV antifreeze, and what their “active ingredients” are.

What kind of RV antifreeze should you use
Click to enlarge

What do we use? Ha! We don’t worry about taste or plumbing deterioration problems. When we winterize, we use air pressure to blast water out of our pipes. What little antifreeze we use goes down the plumbing drain P-traps. I promise you this: We’ve never tasted what comes out of there!


Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.



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Jeff (@guest_255209)
2 months ago

Living in Wisconsin i winterize my camper. I keep my rv antifreeze in an uninsulated shed where my rv antifreeze in the bottles freeze in the winter. Hopefully my RV antifreeze works in the camper during the winter.

Skip (@guest_255027)
2 months ago

I once had some Splash brand antifreeze develop black mold-like substance in a partial bottle. If it will grow in the bottle, I sure don’t want to introduce that into my fresh water tanks!!!

I use the air blow out method from an oil-less compressor to empty my lines after draining the main water tank. If you run the pump after the tanks are empty it will push the water out of the pump. The only time that I had an issue was when I forgot to run the pump. Some rigs have a clear plastic ‘filter’ upstream of the pump that needs to have the bowl unscrewed and emptied or it will freeze. If you run the pump after taking off that bowl then you know that you have air entering into the pump.

Gary Broughton (@guest_254566)
2 months ago

We live in Savannah, TN. We don’t winterize anymore just drain the lines and tank.
Works for us last 7 years.

Bill (@guest_254551)
2 months ago

I have a couple of jugs of Star Brite left over from last winter which I checked. My containers say that they contain ethanol although it is not easy to find any reference to the active ingredient. On the front it has a warning about being combustible. Perhaps Star Brite makes two varieties of antifreeze: one using ethanol and the other PG.

Leonard (@guest_254533)
2 months ago

I blow out the lines with air and put some antifreeze in all “J” traps, drains, grey and black tanks.
After blowing out the lines for my washing machine I drain it and put a little antifreeze in the drum. In the spring I do a quick wash cycle with the washer empty and I am good to go! Zero antifreeze in any potable lines or tanks.

Neal Davis (@guest_254457)
2 months ago

We travel year-round and have never winterized. We keep our RV powered with 50-amp service and the thermostat at 45° F when not traveling. Winters here in Southern east Tennessee are pretty mild with overnight temperatures usually in the 20s or higher. Our January and February travel is usually into Georgia and Alabama, where it is similarly warm or even warmer.

I really like the idea of using forced air to clear water from plumbing. That seems an easy thing to reverse should a camping trip suddenly offer itself.!

Marty (@guest_254426)
2 months ago

I have been using Supertech for years with great success. I live in Colorado, so we get some extreme cold spells. Never had any system damage or lingering taste. Using air has crossed my mind, but can it clear out the water pump completely? not sure… However, air hoses from compressors, and the air intakes to the compressors are not necessarily very clean, so you can introduce dirty air into your clean water system, so it is advisable to do a very good chlorine sanitizing at the beginning of the next season using this method.

Mikal H (@guest_254402)
2 months ago

Just blowing out the lines doesn’t cut it if there are appliances like a washer or dishwasher in the unit.

Also, many people think that a -20F label, for example, on the product means it won’t freeze until that temp. It will turn slushy and then solid before the listed “burst point” on the product. So don’t be surprised if at 0F you see it frozen. But it shouldn’t expand enough to cause damage until the listed burst point.

If you do blow out and then just do p-traps, I recommend also putting some in the toilet bowl to keep the seal wet and also some in the holding tanks to flow down to the spade valves.

Bob (@guest_254401)
2 months ago

I had always used the Camco Easy Going stuff. It is now impossible to find. I think Camco discontinued the product. It doesn’t even show on their website.

Jesse Crouse (@guest_254373)
2 months ago

I use the dealer where we bought our 40′ DP. The bigger coaches are more complicated and expensive to repair. They offer a freeze warranty when they do the job. In 6 years no problems.

Dan (@guest_254348)
2 months ago

Used mostly Walmart Supertech for years and years. Water and bleach flush in the spring, no issues yet.

Jim Johnson (@guest_254341)
2 months ago

We had one used camper where the previous owner used ‘pink stuff’ anti-freeze. It took several times the capacity of the system to flush out the residual taste. Other than traps and a little into the tanks, I use compressed air. My older oilless compressor didn’t have an intermediate regulator. Which meant using a gauge to safely ‘inflate’ my system, stop the input, allow the pressure escape, and repeat until nothing greater than moist air came out of taps. I bought a newer compressor with an intermediate pressure regulator and a larger air storage tank. Now I just hook it up to the city water inlet (after system draining* and clearing the water pump) running at 30-35psi and move from valve to valve.
*after opening the low point drains, the fresh water tank drain and hot water heater, I use an inexpensive plastic hand operated fluid transfer pump to pull out more of the water from the hot water tank and fresh water tank (I have separate fill points for the tank and city water – although it should be possible to feed a smaller tube through the air vent when the two use a single water input point.)

Tom (@guest_254337)
2 months ago

Extremely important. We blow our lines clean, and only use RV antifreeze in the P traps. Far enough South, so not a major concern.

Mark (@guest_254325)
2 months ago

Regarding using air to blow out the pipes instead of using antifreeze: I’ve done that for years in houses that will sit empty for the winter. Now I’m a new RVer and wondered if you would share your procedure. Do you hook up your compressed air to the RV city water connection and push the water out thru the faucets, to the faucets and and blow back to the tanks, or ? (Don’t want to cause problems with my Nautilus water control center!)

Dan M (@guest_254292)
2 months ago

I’ve used a ton of the Splash antifreeze, as well as some of the Prestone and Super tech. But I use them to keep my holding tanks from freezing in the winter (at least, I used to. Now I’ve got tank heaters) since I full time in my camper for work. After the first time I had my pipes freeze (well above where the manufacturer said they would work down to) I took advantage of my floorplan to re-run all my water lines inside under the cabinets. They can’t freeze if they’re up in the heated space with me. As for issues with the ethanol antifreezes I didn’t seem to have any problems, though they weren’t full strength since I was mixing them into the contents of the tank to keep it from freezing.

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