How To Winterize Your RV’s Plumbing System With An Air Compressor

Winterizing your RV’s plumbing is incredibly important, especially if your RV will spend any time at all stored in sub-freezing temperatures. Frozen water lines can quickly lead to burst water pipes, a broken water pump, and a devastating amount of damage to the RV itself. Proper winterizing of your RV’s plumbing system is something almost all RVers need to know how to do at one point or another.

In a recent post on winter RV camping, we shared some helpful ideas to make your winter RV trips more tolerable enjoyable. In this post, we’re sharing a tip for RVers who will be storing, instead of wintering in, their rig.

Blowing Out RV Water Lines vs Using Antifreeze

There are a couple of different ways to winterize an RV. One involves pumping RV-safe plumbing antifreeze into the RV’s water system. In our opinion, this isn’t ideal for a number of reasons, not the least of which is the unnecessary use of RV antifreeze (and the plastic containers it comes in). There’s also the issue of RV antifreeze sitting in your RV’s entire plumbing system for months. The antifreeze is non-toxic, of course, but still – why use gallons of it every season if it isn’t necessary?

Another drawback of winterizing an RV using antifreeze is the need to DE-winterize when the warmer weather returns. In essence, this means going through the winterizing process in reverse, requiring both time and lots of water to thoroughly flush any residual antifreeze out of the system so your water doesn’t taste/smell weird.

Those are some of the reasons why we prefer winterizing our RV with an air compressor. However, you shouldn’t use just any air compressor. For example, you don’t want to use a portable air compressor with a tank (often referred to as a pancake compressor) because they can introduce oil or other contaminants into the freshwater system. They can also take up quite a bit of space.

This type of air compressor has a tank that could introduce oil and other debris into your fresh water system.

What Do I Need to Winterize My RV With an Air Compressor?

If you’ve followed us for any length of time, you’ve probably learned that one of our favorite pieces of gear is our Viair 400P-RV portable air compressor. We’ve used this thing for YEARS (so we’re speaking from extensive experience), and we absolutely love it. Not only is it tankless, but it also has a built-in air filter to prevent debris and contaminants from entering the system.

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You may have seen our post last winter entitled “Which is the Best RV Air Compressor for You?” In that post, we looked at a number of air compressors and explained why we love our Viair 400P-RV so much. But we waxed poetic about the 400P-RV long before that post. In fact, we used our Viair portable air compressor not only to fill the massive high-pressure tires on our old 43-foot diesel pusher but also to winterize our plumbing system when we were planning to be away from the RV for a couple of months during the winter.

In order to accomplish the latter, we had to create our own little winterization kit for our Viair 400P-RV with a blow-out plug, an adjustable air pressure regulator, and male and female quick-connects. The system worked great, and we had a winning kit for winterizing our RV with an air compressor.

Viair must have seen our YouTube video (😂) demonstrating our winterizing kit, because not long after our video came out, they created one of their own just like it! This makes it easier than ever for anyone with a compatible Viair portable air compressor to winterize their RV using their air compressor, without having to make their own winterizing kit.

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What You’ll Need:

To winterize your RV using an air compressor, you’ll need an air compressor (of course) and you’ll also need a couple of other items.

If you already have a Viair compressor that’s compatible with the Viair winterizing kit, you’ll only need the compressor and kit, as well as a couple of gallons of RV antifreeze (yes, there are still a couple of places you’ll want to use that… just not throughout the system). If you don’t have a Viair air compressor and winterization kit, you’ll need the following:

• Air compressor (the Viair 400P-RV is our favorite, also available at MobileMustHave.com – Save 5% with Discount Code RVGEEKS)
• Viair Winterization Kit – OR, if you don’t want to buy this kit, make your own using the following parts:
  • Blow-out plug
  • Adjustable air pressure regulator
  • Male quick-connect plug
  • Female quick-connect
• RV-Safe Antifreeze (You’ll need a small amount for protecting your p-traps, etc. NOTE: if you have a hydronic heating system like an AquaHot or Oasis system, check the owner’s manual for any antifreeze requirements and additional steps needed to winterize the system.)

How Do You Winterize an RV with Compressed Air?

We’re glad you asked! Here are the basic steps to follow to winterize your RV using an air compressor. Your RV may be different from ours, so the procedure may need to be adjusted accordingly.

The day before you plan to winterize, open the fresh water tank’s low point drain and shut off the propane and the electricity to the water heater.

Then, on the day you’re going to winterize your RV:

1. Dump and flush your black and gray tanks. (Following our video instructions here.) Leave the gray valve open and your sewer hose connected when finished.
2. Disconnect the city water supply and turn off your RV’s water pump.
3. Open the pressure relief valve on your RV’s water heater, and remove the drain plug or anode rod.

First, open the pressure relief valve. Then remove the drain plug (Atwood heaters) or anode rod (Suburban heaters). Stand out of the way and be prepared for water to flow out of the water heater.

4. Using a tank rinsing wand, flush your RV’s water heater to clean out any loose scale and debris. If you’d like to watch our step-by-step DIY tutorials on water heater tank cleaning, you’ll find the Atwood video here, and the Suburban video here (with an important follow-up about anode rods here).
5. Attach the blow-out plug. For RV’s with a typical fresh water connection, you’ll attach the blow-out plug directly to the water connection. For RV’s with a permanent hose on a reel like ours, you’ll attach the blow-out plug to the end of the hose.

Attach your blow-out plug directly to your fresh water connection, (or directly to your hose if your RV has a permanent built-in hose).

6. Set the inline air pressure regulator to a maximum of 45 PSI to ensure the pressure supplied by your air compressor doesn’t exceed the allowed limits on your RV’s plumbing (be aware, you MAY need to set it lower… not all RV plumbing can withstand 45 PSI)
7. Connect your compressor to a power source and turn it on.
8. Close the pressure relief valve on your water heater and pull the trigger of your air compressor wand. It’s not important to get every drop of water out of the water heater. The important piece is draining all the water from the lines leading into and out of it. Give the wand an extra squeeze or two until there is just a trickle of water coming out of the heater.
9. If you have a Suburban brand water heater, then you have an anode rod that you removed to drain the water heater. Depending on the condition of the anode rod, this may be a good time to replace it.

The anode rod on top has served its sacrificial purpose well and is ready to be replaced with the new anode rod on the bottom. It might have enough material on it to make it another year, but they’re cheap insurance, so why risk your water heater’s tank?

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9. Reinstall your drain plug or anode rod using plumber’s tape (wind several wraps around the threads). Tighten into place.
10. Turn your water heater bypass valves to the bypass position.

Your water heater’s bypass valves allow you to bypass the water heater when winterizing the RV.

11. If you have a whole-house water filter, unscrew the housing, discard the water filter, empty the remaining water out, and reinstall it without a filter.
12. Open the hot and cold low point drains of your RV.
13. Turn on every faucet in the RV set to “warm” to allow all water to easily run out through the low point drains.
14. If you have a water filter under your sink or an ice maker, turn the bypass valves and remove and discard the filter(s). Instead of a bypass valve, some RVs come with a short length of tubing, which takes the place of the discarded filter during storage.
15. When water is no longer running out of the low point drains, close the valves and turn off all the faucets in your RV.
16. Turning on one faucet at a time set to “warm” to open both hot and cold lines at the same time (or each side separately if you prefer… that works, too!), blow compressed air through the system one or two times until the water clears out of the faucet. If you don’t have a helper inside the RV to monitor this for you, a couple of 15-second blasts or 30 seconds total should blow the water line out sufficiently. Repeat this process at every faucet, and don’t forget your showerhead, kitchen sprayer, water dispenser, toilet, and toilet sprayer if you have one.
17. Check your manufacturer’s instructions for draining your ice maker if you have one.
18. If you have a dishwasher and/or washing machine, turn them on, blow out the lines, then shut them off. Follow any additional steps recommended by the manufacturer for RV winterizing. If your RV is pre-plumbed for a washing machine but you don’t have one, you still have to blow out the lines. Open each side one at a time and have a bucket or pitcher handy to catch any water that sprays out as you do so.
19. Pour a cup or two of RV antifreeze into each of your RV’s sink drains to protect the p-traps from freezing. Don’t forget the shower drain.

Pouring a little non-toxic RV antifreeze in all of your RV’s p-traps and in the toilet is part of the winterization process.

20. Pour about two cups of antifreeze into the toilet and flush it. Pour two more cups or so of antifreeze into the toilet and leave it there.
21. To protect our water pump from freezing, we pump it dry. To do this, we turn on our outdoor shower and our water pump and run the shower for about 15-20 seconds. Don’t run it dry for too long or you could risk damaging the water pump.
22. Blow the remaining water out of the outdoor shower with the air compressor.

Use the air compressor to blow the remaining water out of the outdoor shower.

23. To clear water from the fresh tank fill line, turn the “tank fill” valve on and blow it out. This will blow a small amount of water into the fresh tank, but that’s not a problem, and nothing to worry about.
24. With a backflow preventer inline, we attach the air compressor to the black tank flush and blow it out as well.
25. Close the fresh water low point drain.
26. Close the gray valve.
27. Detach your RV sewer hose and store it for the winter.
28. Open all faucets in the RV and leave them open.

If you’d like a clearer picture of the entire procedure, watch our video below for step-by-step visuals of the entire process!

Conclusion

If winterizing your RV with an air compressor is in your plans this year, we hope this information will prove helpful to you as you navigate the process of winterizing your RV’s plumbing system.

Remember, when in doubt (or when you see something that’s different from what you see on our RV), check your owner’s manual for the recommendations of your RV’s manufacturer.

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