Preparing your RV for Winter Storage
By Mark S. Nemeth  #45776

This article originally ran in the September/October 2001 issue of
Escapees magazine
Reprinted by permission

Here we are, enjoying the beautiful Fall weather. It seems like winter is a still a long way off, but it's coming. As the weather turns colder, the Snowbirds begin to migrate South for the winter to avoid the freezing weather. However, a lot of Rving folks don't have migration as an option and will be faced with storing their RV for the cold winter months.  As the leaves fall around us and the approaching winter is just beginning to threaten, it's time to talk about winterizing your RV for it's long winter nap.

If you will be storing your RV in sub freezing temperatures, there are a number of things that you must do to protect your rig. Motorhomes require a bit more preparation than towables, but the basics are the same, no matter what kind of RV you own. The first thing that we need to do is protect the plumbing in the RV from freeze damage. It is critical that you take the proper precautions to protect your plumbing from freezing, or you will be faced with some nasty surprises come springtime.

To prepare your rig's plumbing systems for winter storage:
1. Drain all tanks. Flush out the black water and gray water tanks and be sure to get them as empty as possible. Drain the fresh water tank.
2. Drain the water heater and close the drain valve.
3. Drain fresh water plumbing system using low point drains if provided. Open all faucets and step on the toilet pedal as well. Get as much water out of the system as possible. Close the low point drains.
4. If your rig is equipped with an icemaker or washer/dryer, follow the manufacturer's recommended procedures to winterize and protect these appliances.

Now, you have a choice... you can either protect your fresh water piping by using a non-toxic RV approved antifreeze or you can use air pressure to blow out the remaining water in your water lines. Both methods have advantages and disadvantages. Using RV antifreeze is probably the surest method to absolutely guarantee that no pipes will freeze. Properly used, it will protect your rig well down into sub-zero temperatures. It does require a lot of flushing in the spring to get the taste out and also makes it desirable to install a water heater bypass to reduce the quantity of antifreeze used.

NEVER use any antifreeze or substance in your fresh water system unless that product is
specifically labeled as non-toxic and safe for use in drinking water systems. Use only antifreeze designed specifically for RV water systems!

Depending on the size and complexity of your plumbing system, you will probably need 1-3 gallons of antifreeze. If you don't have a water heater bypass, better add 6 or 10 gallons to that, depending on the size of your water heater! In order to easily pump the antifreeze throughout your water system, you can install a neat little valve on your water pump inlet piping that allows your pump to draw antifreeze directly from the bottle. It's available from most any RV parts source. Your rig may already be equipped with one, so check the pump inlet first before you run out to buy one. Alternately, you can remove the existing hose from the inlet side of your water pump and attach a short piece of hose to reach into the antifreeze bottle.

Bypass the water heater if you can. If you have an ADC cartridge water filter under the sink, remove the cartridge and install the manufacturer's antifreeze diverter. If you have a generic cartridge type filter, remove the filter element and replace the cartridge holder. Now, run the pump and open each fixture, allowing it to flow until you see pure antifreeze. Monitor the level in the antifreeze bottle and make sure it doesn't run dry. Remember to flush the toilet and operate the toilet sprayer if installed. Don't forget the shower head and the outside shower if you have one. Last but not least, shut off the pump and remove the screen and washer from your city water inlet.  It should be possible to push the anti-backflow valve in the city water inlet with a finger or screwdriver to allow the water to be purged out and antifreeze to flow. Be careful that it doesn't spray all over you! Once you have done each and every fixture in the rig, you should have full protection against freezing pipes in your freshwater system. Now, you need to dump the accumulated water from your holding tanks.

Instead of using antifreeze, you can use air pressure from a compressor to blow the water out of your fresh water lines. This method is cheaper than the antifreeze method and you won't have to flush the antifreeze taste out of your water system come spring. On the down side, however, it is extremely hard to get every last bit of water out of the lines and if sufficient water collects in a low point or valve, then it may be damaged by freezing. Plus, there are portions of the water system that blowing the lines won't clear and you must drain them manually. Still, many people prefer to use air to clear the lines, rather than deal with the antifreeze.

To start with, you will need a little plug (commonly called a Blowout Plug) that will fit into your city water inlet and provide a fitting to connect the air compressor to. Hook up your air source and set it for a max. of 50 psi. Once pressure is applied, go through the rig, starting with fixtures closest to the inlet and open them briefly, allowing the air pressure to blow the water out. Remember to flush the toilet and operate the toilet sprayer if installed. Don't forget the shower head and the outside shower if you have one. Once you have done each and every fixture in the rig, you should have most of the water out of your freshwater system. Remove the air source and bleed off any remaining pressure by opening a faucet. Now, it will be necessary to remove the outlet line and inlet line from your fresh water pump and drain them manually, as the check valve in the pump prevents the air from clearing these lines. Remove any cartridge from any under sink filter and make sure the fixture is drained. Your freshwater system should now be in good shape for the winter storage months.

Now, you need to pay attention to the other plumbing systems in the rig....

1. Pour a small amount of RV antifreeze down each drain to protect the trap.
2. Close the toilet flush valve and pour a dab into the toilet.
3. I suggest that you leave the black and gray water tank valves closed during storage. Leaving them open can cause problems with the seals and can lead to leaks down the road.

OK, now that the plumbing's safe, it's time to think about the rest of the rig.

1. Remove all freezable foodstuffs and cleaning liquids from the rig. Check under the sinks and in the storage compartments and be sure to get it all. Even canned foods can freeze and possibly split open and cause a mess.
2. Shut down the refrigerator, give it a good cleaning inside and prop the doors slightly open.
3. Close the LP gas tank valve(s).
4. Retract all slideouts and retract and stow any awnings.
5. Decide how you will deal with the batteries in your rig during storage:

  • If you will be storing your RV in a location where AC power is not available then it is best to remove the house batteries and the starting battery (if applicable) from the RV and store them in a place where they won't freeze. A discharged battery is more likely to freeze than a fully charged one. Your best bet is to charge the batteries once a month during the storage period and keep an eye on the water level. Remember: never store a battery in an area where it will be exposed to extreme heat or where sparks can occur. Proper ventilation is needed to disperse hydrogen fumes given off by the battery.
  • If you don't wish to remove the batteries from your rig, then it is important to disconnect them so that parasitic current drains will not run the batteries down during storage. You will still need to top off the charge once a month during the storage period. It's also a good safety precaution to unplug the AC supply to the 12 volt converter when you disconnect or remove the batteries. This will prevent the converter from running without the batteries connected if you should hook the rig up to AC power or run a generator. Many converters depend on the load and filtering characteristics of the batteries to provide proper voltage regulation.
  • If you intend to keep your RV hooked to shore power, then the batteries can be left connected. You need only to check the water level in the batteries at least once a month. Constant charge current from your converter will boil out some of the water, so don't neglect this step or your batteries will be bone dry come spring! Remember that in most motorhomes, keeping the RV plugged into shore power will not keep your engine starting battery charged. You will need to charge it periodically using an external charger or buy a battery maintainer and keep it plugged in.
  • 6. Cover all external vents, such as the furnace outlet, to prevent critters from entering. Make sure that there are no easy routes for mice into your rig by covering or duct taping possible access holes.
    7. Check the condition of the roof, roof vents and roof seams and correct any possible leak producing conditions. Now is a good time to take a close look at the whole exterior of the RV and take care of anything that needs fixing.
    8. Check tire pressures. Bring all tires up to the max. pressure rating as found on the sidewall. You may want to cover the tires to prevent weather and sun damage.
    9. For motorhomes, fill gas tank to the top. This will help prevent condensation in the tank. Fuel stabilizer may also be added to gasoline fueled vehicles. Follow the directions on the product that you choose. For diesels, follow the manufacturer's recommended storage procedures. Many folks like to change the oil and filter before storage… this is a good idea, as used motor oil contains acidic compounds that can cause corrosion and damage inside the engine.
    10. Check the condition of the antifreeze in your motorhome or tow vehicle radiator. A tester can be purchased at any auto parts store. Add antifreeze as needed or consider having the system flushed and new antifreeze put in.
    11. If you have a generator, be sure to winterize it also, following the manufacturer's recommended storage procedures.
    12. Consider leaving one sheltered window open just a crack and then also open a roof vent just a bit at the opposite end of the rig. This will provide some air flow through the rig and will help prevent musty odors or mildew. Some folks like to leave a small source of heat inside the rig to help keep condensation down. A 40 watt light bulb is a safe source of heat and will be inexpensive to run.
    13. If you are REALLY industrious, wash your rig thoroughly and apply a coat of good quality wax or protectant to help protect the exterior from the ravages of the winter weather.
    14. If you want to cover your RV, be sure to get a good quality cover that can be secured to the rig and make sure it is constructed of breathable materials. A plain plastic tarp may do more harm than good if it allows moisture to build up underneath it!

    OK, that should just about take care of your winterization. During those winter months, stop by periodically and check the inside of the rig for any developing leaks or problems. Keep those batteries charged, wherever they are. With a little effort now, your RV will be ready to wake up next spring and spend another carefree summer on the road!

    A few fulltimers love to stay up north and enjoy the snow and cold. I find that hard to believe, but then I'm one of those Rvers who prefers to run south when I see a snowflake falling. For those of you who desire to live fulltime in your RV in freezing weather, I'll discuss some tips and tricks to make your winter warmer in our next issue.

    This page last updated on September 8, 2002