Sunday, January 29, 2023


Ask Dave: How do I purge the antifreeze when dewinterizing the RV?

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. Today he discusses removing the antifreeze when dewinterizing the RV.

Dear Dave,
In October 2021, we winterized our 35′ travel trailer by putting antifreeze in the fresh water tank and pumping it thru the lines. We did this because we didn’t have any way to blow out our lines and we were working on a quick timeframe because the park was going to put it in storage. Please give me your recommendations for dewinterizing our TT. Thank you. —Bob

Dear Bob,
Dewinterizing might be a little “wishful thinking” at this point. However, thanks for the question – it’s a popular topic.

The first thing I would do is dump any RV antifreeze that may still be in your fresh water tank. Hopefully you used a non-ethylene RV antifreeze that is made of either ethanol or propylene glycol, as they are nontoxic and biodegradable.

Dispose of antifreeze property

However, even though it’s biodegradable, you should not dump it on the ground. Rather, it should be dumped in a dump station or put in a container and dump it down a drain such as a toilet that routes to a sanitary district for treatment. I checked with our local Sanitary District supervisor. He said that was the proper way to dispose of RV antifreeze – not on the ground or storm drain. Then fill the fresh water tank to about ½ or more with fresh water and add either a cup of bleach or fresh water tank sanitizer and drive around the block a few times to mix it up and dissolve with the RV antifreeze that is left over.

Dump this, as well, and fill your tank back up to ½ full, replace the drain plug on the water heater, and turn the bypass valve if you have one. This might seem a little overkill to some. However, I find it works well to start with fresh water in the tank so I don’t have the “slippery” residue of the RV antifreeze.

Turn on your water pump and go open the farthest faucet from the pump until clear water comes out. Do this for both the hot and cold. Then work your way back doing the same to all faucets, shower head, toilet/sprayer, and outside shower.

Ice maker

Don’t forget the ice maker if you have one. In October you should have removed the filter and replaced it with a cap, shut off the supply, and run a few cycles to get all the water out. Most people don’t run RV antifreeze up into the ice maker. If you did, you will need to cycle it several times to get clear ice.

For those of you reading this that have a winterizing valve that allows you to put a hose into the RV antifreeze jug and not fill the fresh water tank, you can just fill the tank once. You still want to go through the tank and water pump rather than the city water fill as you would have RV antifreeze in the lines to and from the pump as well as the pump itself.

There is a lot more to dewinterizing, such as checking out the propane system, looking for rodents and leaks inside, and much more. I’ll write an article and post after the show season in more detail. This is just for the water system.

Read more from Dave here


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Bob p
29 days ago

Someone didn’t bother to read their owners manual!

1 year ago

Oh No!!! RV antifreeze in the freshwater tank may take along time to get rid of the taste and feel. Sorry that happened. Hopefully you didn’t fill you water heater too!

1 year ago

Egads! Don’t put RV antifreeze in your fresh water tank!

Dick and Sandy near Buffalo, NY
1 year ago

The first statement I start off with is Mother Nature does not care how small or big your RV is or how little or extensive your water system is. You are responsible for your RV and winterizing is done by many. What method you use and how you go about it is hopefully correct in protecting your water system. The larger the RV the larger and more complex the water system. Ours is complex with the additional items as a bath and a half (2 toilets and 2 bath sinks), a stacked washer/dryer and a residential fridge with an ice maker, besides the shower, water tank with by-pass, outside shower hoses, dual kitchen sinks, dump tanks, fresh water tank and water pump. I can not afford to have any freeze problems with much of the water lines inaccessible in our coach. If you have ever seen a large coach being built, much of the water and electrical systems are installed before the walls and cabinetry are put in. So using air is not an option for us. Happy New Year

Bob p
29 days ago

I had a 38’ MH and always used air, it simple pressurize to 40 psi and starting with the water outlet farthest away from the air input point you open the valve until nothing but air comes out, then move to the next valve, if it’s a toilet hold the foot valve open until nothing but air comes out. Working your way back to the input source you have emptied the water out of your lines. Drain the water heater first or you’ll be blowing 6-10 gallons of water out of your hot water faucet. When all finished empty your holding tanks.

Dick and Sandy near Buffalo, NY
1 year ago

One thing I did not see mentioned is that RV Antifreeze is reusable, If when de-winterizing you have a low water drain for both the hot and cold water system, you can drain most of the RV Antifreeze back into the original jugs (or other containers) and reuse it next time cutting down on your next winterizing expense. If not dispose of properly as explained in the article. Stay safe, Stay well and Happy New Year to All.

Richard genovese
1 year ago

Easy peasy….buy three 1.75 bottles of 100 proof CHEAP vodka…cut it with water in half..add a touch of red food coloring…put it in your fresh water tank and run it through all your lines until you see the red color. In the spring drain it through your lines and you will have a nice clean system. If smart reuse the mix for the next time…

Last edited 1 year ago by Richard genovese
1 year ago

By nature I am very cautious. I use a blow out plug and set my compressor to 40 PSI and blow out the lines. I then put RV antifreeze in the lines including the dishwasher, and washing machine. I let it sit for a day or so and use my compressor to blow it out and save it for re-use.

1 year ago

We winterize/dewinterize several times during the ‘off season’ as we use our rv all year. Never put antifreeze in the fresh water tank as it’s too much trouble to clear and it’s not a likely problem area for freezing issues. Don’t forget to pump some into the black tank wash down plumbing.

Bob p
1 year ago

All that mess is why I bought a $39.95 air compressor at harbor freight and blow the water out of the system. The first TT I bought I spent all that money buying the antifreeze, then pumped it through the system, then spent about 3 hrs cleaning it all out in the spring. Now I blow it out, pour a cup full down each drain and it’s winterized, in the spring refill the water and as soon as water goes down the drain it’s dewinterized. Lol

1 year ago
Reply to  Bob p

For those RVer’s who own a large Class A with an Aqua-Hot System, blowing out the lines will NOT work for the Aqua-Hot unit. You will end up with a cracked fresh water loop line inside the Aqua-Hot and a $15000 repair bill. The Aqua-Hot company recommends using RV Antifreeze to winterize the Aqua-Hot water line.

1 year ago
Reply to  Dr4Film

You mean $1500.?

Dave Telenko
1 year ago
Reply to  Dr4Film

WOW $15,000.00 repair bill! Kinda have to think that was a typo, $1,500.00 would sound more reasonable.

Bob p
1 year ago
Reply to  Dave Telenko

It’s his story and he’s sticking to it.

Bob p
1 year ago
Reply to  Dr4Film

Admittedly I know nothing about your system but I don’t understand your answer about a $15000 repair bill. When I blow my system out I leave the air blowing until no water is coming out including the water heater. What little water may be left is not going to create any problems. Yes my manufacturer recommends antifreeze, they have vested interest in promoting the use of antifreeze. As stated in the original post I’ve been doing it this way for 42 of the 43 years I’ve been RVing. The first year I did it like the book says, after the labor involved in cleaning out the system I researched (without the use of computers) and found a better way. Do it the way you feel comfortable, you’re not going to offend me, I’m offering an easier way.

Leonard Rempel
1 year ago
Reply to  Bob p


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