Monday, December 5, 2022


Not all RV antifreeze is created equal


By Russ and Tiña De Maris

abarndweller on

If your rig is sitting in cold country and you haven’t already done so, it’s high time to get it winterized. We’ve written on this important subject before. Keeping your RV water lines from freezing (and breaking) is serious stuff. One question that pops up when discussing winterizing is this: Is there a difference in the types of RV antifreeze?

Most RVers are savvy enough to know there’s a huge difference between RV antifreeze and automotive antifreeze. In case you missed it, here’s a quick recap. RV antifreeze is nontoxic and meant for pumping into the plumbing system. Automotive antifreeze is a whole different critter. Many types are toxic, and should only be put into an engine cooling system.

So when asking what kind of antifreeze they use to winterize their rig’s plumbing system, many RVers respond, “Oh, I use the pink stuff.” Huh? Just what is the “pink stuff?” There really is a difference in RV antifreeze formulas, and it can make a big difference in how things turn out.

There are two basic contenders in the world of nontoxic RV antifreeze. The primary components are either ethanol or propylene glycol. You may remember from your high school chemistry class that ethanol is the “kick” in Kickapoo Joy Juice – grain alcohol. Yes, ethanol is a good antifreeze (not in your bloodstream) because it lowers the freezing point of water.

That other antifreeze contender, propylene glycol, is also an alcohol of sorts. Technically a “double alcohol,” this is not like a “double shot.” But like grain alcohol, it also raises the freezing point of water. For our purposes as RVers trying to keep our pipes from breaking, either one will do the job. At that point, frugal RV logic would ask, “What’s cheaper?” Some retailers would have you believe that the ethanol-based antifreeze is less expensive and, hence, the product of choice for winterizing.

But hold onto your credit cards for a minute – there’s more than money to be considered. Some RVers have reported that using ethanol-based antifreeze did keep their pipes intact, but unexpected side effects cropped up. At least one RVer says when he took his rig out of the “deep freeze” and began to use it during travel season, the taste from the plumbing was bad, and it took quite awhile to flush the unwelcome spirit out of the system. Some warn that rubber plumbing seals can be adversely affected by contact with ethanol. Since ethanol antifreeze is combustible, if you decide to use it, then by all means keep it away from flame.

Does this mean that propylene glycol antifreeze is the choice for RVers? Here’s one more fly in the ointment. In a news release touting its own brand of propylene glycol antifreeze, Dow Chemical warns against similar products made by others – ones that could possibly be made with recycled products. Can you imagine RVers running out with buckets every spring, catching those precious drops of antifreeze, and shipping them back to some chemical plant for recycling? Nah! But there are some outfits that actually do recycle propylene glycol: airports. When your 707 sits on the tarmac on a chilly day, that stuff they spray on the wings to keep the plane from icing up is typically propylene glycol. Often the runoff is captured and sent to a recycler. The recycled product, warns Dow, could come to you along with other chemical nasties that might not be so potable.

How do you know if your brand of propylene glycol RV antifreeze might contain recycled materials? You wouldn’t from looking at the label. Dow, of course, makes a big noise about its materials being strictly “virgin” in every jug of Dowfrost. To save you trouble, we checked with manufacturers of other popular RV antifreeze brands. Shop at Walmart? Its house brand, Super Tech RV and Marine Antifreeze, is virgin pure. Likewise is Camco’s Easy Going -50 brand. Keep a weather eye open on its other brand, Arctic Ban -50. It is made with ethanol.

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: I’ve never tasted what comes out of there!


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Brian Holmes
2 years ago

Being in the North East I’ve used the pink stuff for 30 years of winterizing the campers I’ve owned. Last year I tried the blow out the lines method and had no issues on start up this season. What a waste of time and cost with the other method. I think though you should blow out the lines then let the residual amount left settle to the low spots then hit it again to make sure you got it all. Then put some pink stuff in the traps and the tanks. A plumber might want to chime in here but I believe if there is still some water in the lines as long as the frozen water can move up the line and not out of the line as when it’s full of water you’ll still be ok.

Mark B
2 years ago

I agree with Russ and Tina’s blowing the air out method. I travel in/out of Minnesota a few times during the winter. Between October and March I have to empty toilet bowl and black and grey tanks, usually as I approach Iowa (depending on where it is dropping below freezing. After letting out fresh water:
1) open the drain valve on hot water heater. I replaced drain plug with a valve so I can drain hot water heater quickly anytime and get mineral sludge out
2) open faucets, shower, toilet hose (wrap hose trigger with rubber bank to keep it open) and start your water pump. Let pump run a few minutes until shower and sinks are mostly sputtering air, then turn off.
3) screw blowout plug onto water inlet. Of course use RVTravel link to Amazon to order something like this:

The blowout plugs have either quick connect (for construction style compressor hose connection) or tire (shrader valve) to use with automotive style tire pumps or small compressors. Let your compressor run for a few minutes to finish pushing water out. Pressure should be 40-60psi to prevent damaging water pipes.
4) leave faucets, hot water heater plug and fresh water drain open during storage so remaining water can dribble out
5) pour about 8 ounces of RV plumbing antifreeze in each of the sink and shower drains and toilet (flush it). You don’t need much.
There is nothing to do after storage, except close all the faucets, fresh water tank and water heater valves and refill your water tank adding a sanitizing solution (could be your own bleach mixture or something like Camco Drinking Water Freshener”

It took longer for me to write this than it will take you to clean out water from your plumbing lines and fixtures.

NOTE: Ice maker and washer require separate purging.

John Koenig
2 years ago

I was in a Walmart earlier today and saw, for the first time, “Absolute Zero”. An RV antifreeze claiming to protect down to -100ºF. At $3+ per gallon, I don’t know how well it will sell.

Geoff Baker
2 years ago

Not if you have an Aqua-Hot or Oasis. Blowing out with air will NOT remove all the fresh water from the 35 ft copper coil in the antifreeze boiler tank. If that ruptures, $6,000 repair bill. A few gallons of RV anti freeze seems a cheap price to pay!!!!

2 years ago

I have used a very different approach. I create a vacuum on the hot water heater drain plug, open the faucets and allow the vacuum to remove all traces of water in the water lines. This leaves bone dry water lines and hot water tank. This method got me through many Winters in Northern Virginia. Never had a line or fitting freeze.
Here in the middle of Florida, not much of a problem.

Richard Izzi
2 years ago

Concerning RV antifreeze. Good point about virgin antifreeze. Last thing you stated is that you blow out the water lines and use the antifreeze in the tanks. Hope you use an oil-less air compressor!!!!!!!!!!! Could be detrimental to have oil residue in the fresh water lines.

2 years ago

I am with Russ & Tina—Blow out the water lines & remove the water tank drain plug–THEN DUMp THE PINK STUFF down the tank drains…EASY PEASSY

2 years ago

Just a tidbit here: Think about how cold it gets where you have your rig. I used to drain my water heater and add pink to my waste tanks. Now….it freezes perhaps a dozen nights a year BUT, when it does, it’s only at that point for less than 6 hours or so. I haven’t bothered doing any winterizing in many years now and all is fine.

2 years ago

An antifreeze is an additive which lowers (not raises) the freezing point of a water-based liquid

RV Staff(@rvstaff)
2 years ago
Reply to  Bob

Ha! Good catch, Bob! Thanks! It’s been fixed. 😀 —Diane at

Mark B
2 years ago

Some confusion might be eliminated if the terms “Engine coolant/antifreeze” and “Plumbing anitfreeze” are used.

Engine coolant/antifreeze is a hazardous waste and can’t be dumped. Larger service centers may have on-site recycling/blending machines. It must be recycled, like engine oil. Engine coolant/antifreeze should be tested for freeze protection every few years; it can break down. There are specific formulations of engine coolant/antifreeze, and they should NEVER be mixed, or you could end up with sludge in your radiator and heater core. Colors for engine coolant/antifreeze mean nothing, as there still is no standard color scheme. Auto manufacturers recommend different change schedules for engine coolant/antifreeze. 30,000 or 60,000 or even 120,000 miles. Still, check your engine coolant/antifreeze with a hydrometer regularly.

These folks put together a good explanation of RV Plumbing antifreeze. I hope RVTravel and CamperGrid don’t mind me posting this link for educational purposes.

2 years ago

As it was noted in the article, Automotive Anti Freeze (usually Green) is highly toxic and deadly! It is absorbed into the plumbing and is virtually impossible to remove from RV plumbing.

There have been cases where people have actually DIED after they thought their RV water system had been flushed out and used the RV water system to prepare food and drinking water. Ethyl Glycol (spelling) is deadly and will kill you, if you get it in your body!

USE THE PINK STUFF that specifically says, NON TOXIC RV ANTI FREEZE! You can purchase it at Walmart!

Joe Testa
2 years ago

There are two schools of thought on the air method:

1. It is ok and quite a few people do it so it must be ok.
2. What is the source of the air? Assuming an air tank, what is in the air tank, when was the last time it was “flushed”? Is there bacteria, rust particles, etc from the air tank that now you’re pushing into your water lines? Does the air method get all of the water out of the lines?

Just some food for thought, I personally only use the “pink” stuff but I’d like to hear what others say.


Tommy Molnar
2 years ago
Reply to  Joe Testa

Well, I’ve been using the “air method” for decades and haven’t experienced any trouble. I use one of those pancake compressors. I fill it when I need it for whatever, then drain the air out with the release, then open the ‘drain’ at the bottom and let it do its thing for expelling anything that collects on the bottom, down to zero air pressure. So far, so good. I wonder if there are filters you could attach to the end of the hose. Must be.

2 years ago
Reply to  Tommy Molnar

Yes there are fine air filters. If you paint with an air gun you use one.

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