How to winterize an RV for a Canadian winter (step by step)

Why winterizing matters in Canada

Water expands as it freezes. In RV plumbing, which is often run through outside walls, underbellies and compartments, that expansion cracks PEX fittings, pump heads, faucet cartridges, toilet valves, water heater tanks and low-point drain valves. Across much of Canada, temperatures well below -20 °C are common in winter, and the Calgary area adds chinooks: warm spells that thaw things out, followed by hard refreezes. Any water left in a low spot gets frozen and thawed over and over.

Use this guide alongside your owner's manual. RVs vary (washing machines, ice makers, outdoor kitchens, tankless water heaters and residential fridges all need their own steps). Print the winterizing checklist to keep track.

Safety: Use only RV and marine antifreeze (propylene glycol based, labelled safe for potable systems) in your fresh water system. Never use automotive antifreeze, which is toxic. Make sure the water heater is off and cool before draining it, and turn off propane and electric modes first. When using compressed air, keep pressure modest (check your RV manual), wear eye protection and open a tap before connecting air so you don't over-pressurize the lines.

What you'll need

• RV antifreeze. Check the burst-protection temperature rating on the jug. Many RVs need roughly two to three 3.78 L jugs when the water heater is bypassed. Larger rigs need more.
• A water heater bypass (many RVs have one built in).
• A pump siphon kit or built-in winterizing valve.
• An air compressor and blow-out plug adapter.
• A socket for the water heater drain plug or anode.
• Basic hand tools, a bucket, rags and a headlamp.

Step 1: Empty the holding tanks

1. Dump the black tank, then the grey tank, at a dump station.
2. Flush the black tank thoroughly (see RV tank sensors reading wrong and black tank clogs: what to do).
3. Leave the valves closed once empty, or follow your manufacturer's recommendation.

Step 2: Drain the fresh water system

1. Turn off the water pump and disconnect city water.
2. Drain the fresh water tank using its drain valve.
3. Open all faucets (hot and cold), including the shower and outdoor shower.
4. Open the low-point drains. Usually there's one hot and one cold line, under the RV or in a compartment.
5. Flush the toilet to drain the toilet valve.

Step 3: Drain the water heater

1. Make sure gas and electric modes are off and the tank is cool.
2. Relieve pressure by opening the pressure-relief valve lever.
3. Remove the drain plug (aluminum tanks) or anode rod (steel tanks). Water will rush out.
4. Inspect the anode while it's out. See RV water heater not working: no hot water on gas or electric.
5. Leave the plug or anode out over winter. Store it somewhere obvious (some people tape it to the RV door) so you remember it in spring.

Step 4: Bypass the water heater

Set the bypass valves so water and antifreeze go around the water heater, not into it. Otherwise you'll fill the tank with antifreeze, which wastes a lot of it. Bypass layouts vary: some have one valve, some three. Check your manual.

Step 5: Remove filters and check special equipment

• Remove any inline water filter cartridges and bypass the housing.
• Check your manual for the ice maker, washing machine, dishwasher and any residential fridge water line. Some need specific procedures.

Step 6: Blow out the lines with compressed air

Compressed air pushes out most of the remaining water. In a climate like Alberta's, many owners use air and antifreeze for extra protection.

1. Close the low-point drains and all faucets.
2. Install the blow-out plug in the city water inlet.
3. Set the compressor regulator to a modest pressure (per your RV manual).
4. Connect the air, then open each faucet one at a time, hot then cold, until only air and mist come out. Don't forget the shower, outdoor shower, toilet valve (hold the pedal) and low-point drains.
5. Disconnect the air.

Step 7: Pump in RV antifreeze

1. Set the pump's winterizing valve (or fit the siphon kit) so the pump draws from the antifreeze jug.
2. Turn on the water pump.
3. Starting at the faucet closest to the pump, open the cold side until pink antifreeze flows steadily, then close it. Repeat with the hot side. (With the heater bypassed, hot lines fill with antifreeze through the bypass.)
4. Work outward through every faucet, the shower, the outdoor shower and the toilet (flush until pink appears).
5. Open the low-point drains briefly until antifreeze appears, then close them.
6. City water inlet: Many inlets have a check valve that can trap water. Push the inlet's check valve open with a small screwdriver until antifreeze appears (with the pump running), or follow your manual.
7. Turn off the pump. Swap jugs as needed and keep the pump from running dry.

Step 8: Traps and tanks

Pour a cup or two of antifreeze into each sink drain and the shower drain to protect the P-traps, and a little more into the toilet so the seal stays wet and the black tank valve area is protected. Some owners add a little to each holding tank. Check your manufacturer's recommendation.

Step 9: Batteries and electrical

• Fully charge the batteries.
• Either remove them and store them somewhere above freezing with a smart maintainer, or leave them in the RV on a maintainer. A discharged lead-acid battery can freeze and crack in severe cold.
• Turn off the battery disconnect if you're not using a maintainer, since parasitic loads like the propane detector and stereo memory slowly drain batteries.
• Lithium batteries: follow the maker's storage guidance on state of charge and temperature.

See RV battery not charging: how to troubleshoot the converter and 12V system.

Step 10: Propane, appliances and interior

• Turn off propane at the tanks. Cap or cover the regulator and keep the tank cover on.
• Empty and clean the fridge and freezer. Prop the doors open.
• Remove food, liquids that can freeze and burst, and anything that attracts rodents.
• Leave cabinet doors and drawers slightly open for airflow.
• Place moisture absorbers to cut condensation.

Step 11: Keep rodents and insects out

Mice can do serious damage to wiring and insulation over a winter. Check for gaps where plumbing and wiring enter the floor, and plug them with steel wool or copper mesh. Screen furnace, water heater and fridge vents with RV-specific covers (remove them before using the appliance). See rodent deterrents.

Step 12: Exterior

• Inspect and reseal the roof before snow flies (RV roof maintenance and resealing: a practical inspection and resealing routine).
• Condition slide and door seals.
• Retract slides and awnings.
• Inflate tires to the correct pressure and cover them.
• Chock wheels. Consider storage-specific tips in RV storage tips for Calgary winters.

Common winterizing mistakes

• Forgetting the outdoor shower, the toilet valve or the low-point drains.
• Not bypassing the water heater.
• Leaving the water filter in place (it holds water).
• Skipping the city water inlet check valve.
• Leaving the pump's winterizing valve in "winterize" position in spring. See How to de-winterize your RV in spring: flush, sanitize and system checks.

When to call a pro

If your RV has complicated plumbing (washer, dishwasher, residential fridge with an ice maker, tankless water heater, hydronic heating), or you're unsure about any step, a certified RV technician can winterize for you. Many shops get booked up in fall, so schedule early.