Winterizing Your Airstream Trailer

Winterizing Your Airstream Trailer

We bought our Airstream trailer with the intent of using it year-round. Not necessarily continuously, as we still own a house that we like quite a bit, but we wanted to be able to use it whenever we wanted, including in the winter. The winter is the best (and most comfortable) time to visit some of our favorite places like Death Valley and the Sonoran Desert. In order to do this, we had to learn about winterization, especially since we live in a climate where freezing temperatures are common and below zero temperatures are possible for a few days each winter.

Airstreams are not four-season trailers. Unless they are used dry (no water at all, no sinks, no toilet, no showers), or are heated continually (using a lot of propane in the process) they are not suited to below freezing temperatures. The water in the pipes will expand when frozen, and break the pipes. Suddenly you have a very expensive problem! How expensive? We hope to never find out!

For many (especially full-timers) the solution is simple: Keep the Airstream in temperatures above freezing. There's a reason that the populations of Arizona and Florida increase in the winter.

For everyone else, and that includes us, we have to winterize the trailer when moving to colder temperatures, and de-winterize after arriving back in warmer temperatures.

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Winterize On Your Own

The winterization process is something that can be done for you at an RV service center, or done by yourself. We advocate the latter (and follow the steps in this post ourselves), for a few reasons:

1. It's really not that hard (if we can do it, you can do it!). It may be intimidating the first time, but then you'll have the process down and it's no big deal going forward.
2. It's quick. The longest part is actually emptying all the tanks.
3. It's much more convenient to be able to do the process yourself. You do not have to be at the mercy of the availability of an RV service center.
4. If you do it yourself, you are more likely to use your trailer during the winter off-season. Having to winterize when heading back home to colder temperatures will no longer be a deterrent to heading out on a trip to warmer temperatures during the winter.
5. You will learn about various systems in your RV as part of the process.
6. It's cheap! Buying a new air compressor or a few gallons of RV antifreeze is much cheaper than having a dealer winterize your trailer.

How To Winterize Your Airstream

Winter in the Tetons again, this time at the famous Moulton Barn (Photo Copyright Ron Coscorrosa)

So that's great, how do you winterize your Airstream? One excellent concise resource, in PDF format, is here. Note that the concepts are the same for any RV, but the specific details might be different. You should always consult your owners manual for specific details for your trailer. We will outline our process below, but your process may be slightly different. For example, you may have a water filter that you need to disconnect, or have a washer and dryer (not likely on an Airstream, but on a different trailer). These steps are offered as a place to start learning about this process and should not replace due-diligence and common sense when applying these tips on your own trailer!

Here are the steps we use on our own trailer (an Airstream 2011 25FB):

1. Drain all tanks (fresh, gray, and black) as well as the hot water tank. First you will have to run the water pump until the fresh water and hot water tanks are mostly empty. If you have gray tank capacity (we usually don't since we are usually doing this at the end of a trip away from hook-ups) you can simply run the shower until the fresh water tank and hot water tanks are empty. We usually have to catch some water in a basin and then dump it into the toilet since we have more black tank capacity than gray tank capacity. Note: you don't want to run the water pump dry as you could damage it. It is important to get "most" of the water out, the rest will be cleared out in subsequent steps. Empty your black tank and then your gray tank using the normal process (you can do this now or at the end of the process, whichever is more convenient).
2. Turn off the water pump - you don't need it for the rest of these steps.
3. Open the valve on the fresh water tank to drain any remaining water (on our Airstream, this is located on the street side near the tires, look for the white valve, see the photos below). There should not be much water left in it at this point.
4. When the hot water tank is cool and the system is turned off, drain the remaining water in the hot water tank. Our hot water tank has a nylon screw (I believe it is 15/16") that you have to unscrew to drain the tank. When it's unscrewed, the hot water just spills everywhere on the ground (see photo below). It's not a well designed system, but it does drain the tank quickly! Once the tank is drained we put the screw back on.
5. Uncap the low point drain lines. On our 25 FB there are two red valves between and behind the street side tires, just behind the white fresh water tank valve (see photo below). There should be a little water but not too much that comes out right way.
6. Drive back home! Going up and down hills will drain most of the remaining water in the lines and fresh water tank. Alternately, you can raise and lower the tongue jack to simulate this process.
7. Blow out the remaining water in the lines with an air compressor. When home, you can close the fresh water tank valve and re-cap the low-point drain lines again. Camco sells an air compressor quick connect adapter that screws into the city water inlet. It's cheap and works very well. Open one of your faucets, and place a large plastic bowl or something similar to catch the water, and then connect the air compressor to the adapter, making sure it is less than 60 psi (city water pressure is usually around 60-70 psi). We are able to blow out the lines with 45-50 psi no problem. Do the same for the hot and cold water for every faucet, the shower, and the outside shower if you have one. You now have NO water left in your lines! Note that a small little DC/cigarette air compressor that you use for tires may have the necessary PSI, but won't have enough air volume. How much volume do you need? I have seen recommendations of 3-6 gallons (this six gallon portable unit at Amazon should work well). We use my father-in-law's gigantic air compressor, but it's overkill.
8. Pour some RV anti-freeze in your sink traps and toilet to keep them from freezing. Note that RV anti-freeze is non-poisonous (unlike automotive anti-freeze). You do NOT want to use automotive anti-freeze, ever, for this process!
9. That's it! You're done with the plumbing winterization! Bring on the below zero temps because it won't matter.
10. You should now take everything out of the fridge (this is good opportunity to clean it). Also take any clothes and food that are in the trailer to discourage rodents. Put the battery use switch into "store" mode and disconnect your batteries. We own AGM batteries which discharge very slowly, so at this point we really are done. If you have different batteries that discharge more quickly, you may have to charge them up periodically. You don't want them to go to zero (and really, you should aim to keep them above 40-50%).
11. To de-winterize, just fill up your fresh water tank like normal (we usually disinfect our fresh water tank first - instructions for that process are easy to find online). You will want to make sure the black tank has a few gallons of water in it too to make it easier to drain later. Don't forget to reconnect your batteries (you probably won't forget).

Winter in the Tetons along the Snake River (Photo Copyright Ron Coscorrosa)

Winterizing with RV Anti-freeze

There is one school of thought (possibly perpetrated by those who sell RV antifreeze) that you need to run RV anti-freeze through your lines. Based on all of our research on this topic, we have decided that this step is not necessary for us. If you do not have access to an air compressor to blow out the lines, you can run RV antifreeze through your lines as an alternative winterizing method.

If you need to run RV anti-freeze through your lines, there are a few additional steps. Keep in mind that the existing water in your lines will dilute the RV antifreeze (the antifreeze doesn't "push out" the water, it mixes with the water). The temperature rating on your RV antifreeze assumes that is not diluted, its actual temperature rating will get worse the more it is diluted. Thus, if your RV will be in really cold temperatures, relying on RV antifreeze without blowing out your lines could invite problems. 

1. Buy 3 gallons of RV antifreeze (it is possible though unlikely you will need more than this, and will likely need less).
2. Close the water bypass valve to your hot water tank (Our Airstream had this bypass installed, see the photo below to see how ours works. You will need to look at your own manual to see how this works for your specific trailer). For us, there are three valves on the side of the hot water tank that we have to turn. By using this bypass the RV anti-freeze will not go in to your hot water tank. If you don't have this or can't install it, you need  an extra 7 gallons or more of RV anti-freeze.
3. Close the low point drain lines if they are open (no need to have antifreeze all over the ground!)
4. Install a pump converter winterizing kit. Our Airstream had one pre-installed. Essentially this enables your water pump to pull from the fresh water tank (normal operation), or, by switching a valve, pull from a hose that you put in your bottle(s) of RV antifreeze. The water pump will pull the antifreeze through the lines for you. Alternately, you can use a hand pump kit but I imagine this is much slower.
5. Pump the RV anti-freeze through the system. Connect the hose to the pump converter winterizing kit, put the hose in your bottle of RV antifreeze, turn on your water pump, and then open each faucet (hot and cold) one at a time until the pink stuff starts coming out. Don't forget the shower and outside shower if you have one. Also remember to put some RV antifreeze in the toilet and sink traps.
6. To de-winterize, flush the lines of anti-freeze with fresh water by turning on each faucet in turn until clear water comes out (you may wish to clean your fresh water tank too and run a little more water through to dilute any residual antifreeze "taste" from the lines).  Afterward put the hot water tank bypass back so you can use the hot water tank again.

Helpful Photos

The low point drain valves (the red valves on the left), and the fresh water tank drain valve (the white valve on the right). Both valves are closed (typical position) and located on the street side of our trailer, between the tires.

The low point drain line valves (red) open, and the fresh water tank valve (white) open. You can use the tongue jack to get a little more water out, but the best thing to do is drive around a little bit.

The hot water bypass valves (the top three valves). This is with the bypass OFF (in other words, water and anti-freeze would go into the hot water tank in this configuration).

The three hot water bypass valves, with the bypass on (meaning water and anti-freeze will NOT go into the hot water heater).

Hot water heater drain valve (you can see the water coming out on the left, spilling all over randomly, great design! We will find a tube next time). There is a nylon screw (15/16" if I recall correctly) that is used to plug the valve.

The water pump converter winterizing kit valve (gold valve on the left). Notice how the valve is pointing to the main fresh water tank line.

The water pump converter winterizing kit valve (gold valve on the left), with the clear siphon hose attached, the valve is now pointing to the clear siphon hose. Now the water pump will suck the antifreeze from the end of the siphon hose (which will be placed in your antifreeze bottle) rather than the fresh water tank.

Final thoughts

We have done both (blowing out the lines and using the antifreeze) and prefer the blowing out of the lines, but both methods work for our situation. Another method is to simply leave your RV in a warm climate - though there aren't many places that stay above freezing all winter. We recently left our trailer near Las Vegas (so that we wouldn't have to drive it home to Colorado and back again, possibly over snow or ice covered roads), but still used the antifreeze method because below freezing temperatures are likely.

If you have any other tips for winterizing your Airstream, please share them below!