RV Winterizing – Preventing Frost Damage


Frost Damage —

Winter is just around the corner or maybe for some northern regions it has already arrived. The days are getting shorter and the nights cooler. Soon frosty Jack will lay his white blanket on the landscape.
Winter means freezing temperatures, most areas in the US and Canada are subject to freezing. One winter, not long ago, during our tour through  southern Arizona temperatures dropped well below freezing raising havoc with RV water lines, many RVs were damaged.
RVs are especially vulnerable to freezing, most are poorly insulated. If you have ever spent a winter night in your RV you know how difficult it is to keep it warm. The furnace runs continually.
Water expands as it freezes, the harder it freezes the more it expands, causing water system damage. Winterizing your RV properly will prevent frost damage.
It is a good idea to take care of this annual chore sooner rather than later. There is nothing more unsettling than bolting up in the middle of a good night’s sleep realizing you have not winterized  your RV and the thermometer is dipping below freezing.

RV Water System

RV water systems start at the fresh water holding tank flows into the water pump. The pump pushes water through the water lines to the faucets, drains, gray and black water tanks, maybe water filters and appliances such as a refrigerator, ice maker, and clothes washer.
All of these items can be damaged by freezing. 
Frost damage can be extensive or confined, affecting your entire system or specific areas. A large leak such as a burst pipe or broken fitting can flood your rig, damaging flooring, and many wood composites that absorb moisture and swell.
Metal fittings will usually fail before plastic, plastic expands more than metal.
RV rot
RV rot
Freezing can also cause slow leaks from loose fittings or small cracks in water lines or drain pipes which can lead to mildew and rot.
If your system will not sustain pressure or the water pump cycles periodically when all the taps and outlets are closed, it’s an indication of a slow leak or a faulty water pump foot valve.

The Sewer System

This system is also vulnerable to frost damage including the toilet, gray water tanks, black water tank, sink and shower drains, valves and vents. Tanks may crack if not drained and drain valves may be damaged if left closed, water can accumulate at the valves and freeze.
If your RV is stored in a part of the country susceptible to cold temperatures for extended periods, other items may be affected by freezing. RV batteries can freeze and crack causing acid leakage and corrosion. Battery replacement is not cheap, especially if you have several.
Any container with liquid can freeze and crack, including canned goods, cleaners, etc. and water hoses if not drained.

Winterizing Equipment 

Before you get started there are a few items you may require. These items can be ordered online through Amazon or most RV parts stores.
I have included the top rated items for your convenience, just click the item to see the description. Take advantage of limited time free shipping on most products.
Non-toxic RV antifreeze (The amount depends on the layout and length of your plumbing lines. Two to three gallons should be enough).



 – Hot Water Tank bypass kit, if not already installed. The bypass valve will eliminate the hot water tank from the system. This will reduce the amount of anti-freeze needed to fill the system. Most hot water tanks hold about 5 gallons, that’s a lot of anti-freeze to buy, the by-pass kit will pay for itself the first year.



 – Holding tank cleaning wand, winterizing is a good time to clean your tank before storage it will help prevent odors.


– Water pump converter kit for pumping anti-freeze through the system.
A quick connect air nozzle attached to the city water inlet to blow out the water lines.
Air compressor to blow out water lines.


The Winterizing Procedure

The procedure is not complicated, but diligence is necessary for proper protection.
Turn off hot water heaters and the water pump, open a faucet to release water pressure.
Locate water system drain valves, hot and cold water lines as well as the fresh water holding tank drain. Their position should be indicated in your owners manual. If you cannot find them call your dealer. Water line drain valves should be located under your RV or inside a lower cupboard with the end of the lines protruding through the underside of your rig. Once located, open drains and also kitchen and bath faucets to allow air into the system to facilitate draining.
The hot water tank requires draining as well, do not attempt to drain the hot water tank if hot or under pressure. There should be a large drain plug (metal or plastic) located inside the hot water tank exterior access panel. Remove the drain plug to drain.
Blow out the system with compressed air. Note: some RVers believe it’s not necessary to add anti-freeze to the system once it has been blown out. Unfortunately, there may be sags in the water lines where water may accumulate and freeze.
Install the hot water tank bypass kit, turn the valve to bypass.
Attach the water pump converter and place the end of the plastic line into a jug of RV antifreeze. Close water line drains and faucets. Pressurize the water system. Open each faucet or water tap one at a time starting closest to the water pump, let the water flow until anti-freeze appears, close the tap and continue to the next one until anti-freeze flows out each tap.
Depress toilet flush pedal or valve until antifreeze flows into the bowl. Leave some antifreeze in the bowl, this will help prevent the flush valve from sticking.
If your RV is equipped with water filters they may be located in several places, under the kitchen sink, in an interior or exterior storage compartment. The fridge may also have a water filter. Remove filters, drain and replace.
Once RV anti-freeze has been pumped through the system go outside to the city water inlet. Remove the small screen over the inlet, using a small screwdriver, push in the valve until antifreeze flows out. Replace the screen and turn on exterior showers or spray hoses until anti-freeze flows out.
Add a cup of anti-freeze to the sink and shower drains, there is a “P” trap below each drain. The “P” trap is a “U” shaped bend in the drain pipe containing water which prevents gray tank gasses from coming up the drain and into your RV.
Gray and black tanks require flushing and draining, it is not necessary to add anti-freeze to these tanks as long as the dump valves are left open. If your RV doesn’t have a built-in tank flushing system clean the black tank with a wand, or use a product like Flush King to clean both the black and gray tanks.
Lubricate the dump valves with WD40. If you leave these valves open attach the sewer drain cap to prevent critters from entering and building nests. If you prefer to close the dump valves pour a few cups of anti-freeze into your toilet and sink, this will flow to the drain valve preventing damage from any residual water that may accumulate.
Consult your owner manuals for winterizing ice makers, refrigerators, and washing machines. Most of these appliances have a winterizing cycle.
When storing your RV leave a window or a window and a vent slightly open to allow air exchange to prevent dampness and mildew. If your RV does not have one consider installing a vent cover.


Now that the inside is ready for winter we can move to the exterior. The outside is less complicated, although there are still several items that need attention.
Lubricate latches, locks, and hinges with a light  oil, this will help prevent rusting and seizing. Lubricate slide out gears, wheels, tracks and rubbers with the appropriate product. A dry lubricant is best, it will not attract dust.




 Wash your rig and wax if necessary, waxing will help prevent decals from fading and peeling. Apply tire treatment and cover the tires, this will help prevent dry rot extending tire life.


 Check exterior caulking around windows, doors and roof joints for loose and cracked caulking, remove, clean thoroughly and re-caulk for a weather tight seal.


Finally, if your RV is not stored undercover a good breathable cover is essential to protect your investment. A good cover lessens your work in the spring, it should keep your RV clean and maintain the integrity of exterior sealants, wax, and caulking.


I have tried to cover most aspects of RV winterizing and storage, however, your specific unit may have its own special features that need attention, such as a generator.
I hope you have enjoyed this article I am sure this will help with your winterizing chores.
Thanks for visiting
Gord B.

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