RV Winterizing & De-Winterizing Guide
One cold night is all it takes to split a water line and flood a subfloor. Here is exactly how to winterize an RV, travel trailer, or fifth wheel for an Ontario winter — and how to bring it back safely in spring.
When to winterize in Ontario
Water expands roughly 9% when it freezes, and RV plumbing runs through thin, unheated cavities. In Southern Ontario the safe window to winterize is late October to mid-November, before the first sustained freeze. If overnight lows are forecast near -4°C (25°F) for several hours and the rig is unheated, it is already at risk.
Still camping late in the season? At minimum, drain the fresh tank and open the low-point drains between trips. Full winterizing takes about an hour and costs a fraction of a single split-fitting repair with a flooded floor.
Use pink RV/marine antifreeze only. Automotive ethylene glycol is toxic and must never enter a potable water system, even if you plan to flush it.
What you'll need
Gather everything before you start. Stopping halfway with an open water heater is how rigs get missed steps.
8–12 L of non-toxic pink RV/marine antifreeze (more for large rigs)
Water heater bypass kit (most rigs built after 2010 already have one)
Water pump converter kit or a siphon hose for the pump inlet
Water heater anode / drain plug socket and fresh Teflon tape
Air compressor with a blow-out plug, regulated to 30–40 PSI
Basic hand tools, a bucket, and moisture absorbers for storage
How to winterize an RV, step by step
The order matters. Drain first, blow out second, bypass third, antifreeze last — skipping ahead wastes antifreeze and leaves water trapped where it can still freeze.
Drain every tank
Empty and flush the black tank first, then the grey, then drain the fresh water tank. Leave the drain valves open while you work so nothing refills.
Drain the water heater
Make sure the heater is off and the tank is cool and unpressurized. Remove the anode rod or drain plug, open the pressure relief valve, and let it drain fully. Never drain a hot, pressurized tank.
Open the low-point drains
Open both hot and cold low-point drains and every faucet, including the shower, outdoor shower, and toilet valve, until the lines stop dripping.
Blow out the lines
Attach a blow-out plug to the city water inlet at 30–40 PSI and open one faucet at a time — hot then cold — until only air comes out. Don't skip the toilet sprayer or outdoor kitchen.
Set the water heater bypass
Turn the bypass valves so antifreeze routes around the water heater tank. Reinstall the anode rod with fresh Teflon tape once the tank is empty.
Pump antifreeze through
Draw antifreeze through the pump with a converter kit or siphon hose. Run each fixture — hot, then cold — until pink fluid flows steadily, then shut it off and move to the next.
Protect traps and the toilet
Pour a cup or two of antifreeze down every sink and shower drain and into the toilet bowl so the P-traps, holding tank valves, and toilet seal are protected.
Close it up and label it
Close all faucets and drains, turn the pump off, and tape a note on the fresh water fill that says 'WINTERIZED' so nobody hooks a hose up in February.
How to de-winterize your RV in spring
De-winterizing is more than flushing the pink stuff out. It's your first chance to catch freeze damage, failed seals, and expired safety gear before your first trip.
Flush the antifreeze out
Drain any remaining antifreeze, then connect fresh water and run every hot and cold tap, the shower, and the toilet until the water runs clear with no pink tint.
Restore the water heater
Close the bypass valves, confirm the anode rod and drain plug are tight, and fill the tank completely before you ever turn the burner or element on — dry firing destroys an element.
Sanitize the fresh system
Add roughly 60 ml of unscented bleach per 100 L of tank capacity, run it through every tap, let it sit 4–12 hours, then flush until the chlorine smell is gone. Fit a new water filter.
Pressure test for freeze damage
Pressurize the system and walk the rig with a flashlight: check under sinks, behind the pump, at the city water inlet, and in the underbelly for weeping fittings and split lines.
Batteries, propane, and detectors
Reinstall and charge batteries, check terminals, open propane slowly and leak-test the connections, and test the LP, CO, and smoke detectors — detectors expire on a date code.
Roof, seals, and tires
Inspect roof seams and sealant after freeze-thaw season, check slide-out seals, and set tire pressure cold. Tires older than five to six years should be inspected regardless of tread.
Winter storage tips that prevent spring repairs
Most of the damage we repair in April was caused between December and March. These six habits cover almost all of it.
Keep snow load off the roof
Heavy wet snow flexes the roof and stresses seams. Clear it with a soft brush from a ladder — never a shovel or a pressure washer.
Ventilate to stop condensation
Crack roof vents and use moisture absorbers. Sealing an RV airtight for five months is how mould and delamination start.
Manage your batteries
Store lead-acid batteries charged and on a maintainer; store lithium near 50% and never charge it below 0°C without internal heating.
Block out the rodents
Seal underbelly gaps and wiring pass-throughs, remove all food, and check for droppings monthly. Chewed wiring is a common spring surprise.
Take weight off the tires
Inflate to the sidewall rating, park on boards rather than bare ground, and cover the tires to slow UV and ozone cracking.
Shut propane off at the tanks
Close the valves, cap the fittings, and store cylinders upright outdoors. Have regulators tested if they are more than ten years old.
Cold-weather camping tips
Camping through an Ontario winter is absolutely doable — as long as your plumbing never gets a chance to sit cold.
Skirt the rig and keep tank heaters on — an enclosed, heated underbelly is the difference between camping and repairing.
Use a heated potable water hose, or fill the fresh tank and run off the pump instead of staying hooked up.
Keep the furnace running at a low setting rather than switching it off; plumbing runs through unheated cavities the thermostat never sees.
Run a small dehumidifier or crack a vent — a family of four can put several litres of moisture into the air every day.
Add antifreeze to the grey and black tanks and dump only when tanks are at least two-thirds full so nothing freezes in the valve.
Carry a backup heat source and keep propane topped up; a furnace can burn through a 20 lb cylinder in two cold nights.
Watch the CO and LP detectors closely in winter — the combination of sealed windows and combustion heat is exactly when they matter most.
Let us winterize it for you
Our OEM trained technicians come to your home, storage lot, or campground anywhere in Southern Ontario. Flat-rate pricing, quoted before we start.
Common questions
When should I winterize my RV in Ontario?
Winterize before the first hard freeze — in most of Southern Ontario that means late October to mid-November. If overnight temperatures are forecast to hit -4°C (25°F) or lower for several hours, water left in your lines can freeze and split fittings. If you are still camping late in the season, at minimum drain the fresh tank and low-point drains between trips.
How much RV antifreeze do I need to winterize?
Most travel trailers and fifth wheels need 8 to 12 litres (2 to 3 gallons) of non-toxic RV antifreeze when the water heater is bypassed. Large motorhomes with a washer, ice maker, or outdoor kitchen can need 15 to 20 litres. Always use pink RV/marine antifreeze rated for potable systems — never automotive ethylene glycol, which is toxic.
Can I just blow out the lines with air instead of using antifreeze?
Compressed air (set to 30–40 PSI) removes most of the water and is a valid method, but small amounts always remain in traps, valves, and the pump head. In Ontario's deep-freeze winters we recommend blowing the lines out first and then pumping antifreeze through, which gives you a much larger margin of safety. P-traps and toilet seals still need antifreeze either way.
Do I need to bypass the water heater before adding antifreeze?
Yes. A typical 6-gallon water heater would soak up most of your antifreeze for no benefit. Drain the tank fully, remove or open the anode/drain plug, then set the bypass valves so antifreeze skips the tank. Never add antifreeze to a water heater tank.
What does RV winterizing cost?
Mobile winterizing is a flat-rate service that varies with rig size and how many water-using appliances you have. RV Steward gives you the price up front before we start, and we come to your home, storage lot, or campground anywhere in Southern Ontario — no need to tow the rig anywhere.
How do I de-winterize my RV in the spring?
Drain and flush the antifreeze with fresh water at every tap, restore the water heater bypass and reinstall the anode rod, sanitize the fresh water system with a bleach solution (roughly 60 ml of household bleach per 100 litres of tank capacity), flush again, then pressure test for leaks. Also reinstall batteries, check tire pressure and date codes, test propane and detectors, and inspect roof seals before the first trip.
How do I sanitize my fresh water system after winter?
Fill the fresh tank with water plus about 60 ml (1/4 cup) of unscented household bleach for every 100 litres of capacity. Run every hot and cold tap until you smell chlorine, let it sit for 4 to 12 hours, then drain and flush with fresh water until the smell is gone. Replace the water filter cartridge afterward.
Can I camp in my RV in the winter without winterizing?
You can, but only with heated tanks and an enclosed underbelly, skirting around the rig, a reliable heat source running 24/7, and a heated potable water hose. If you leave the RV unheated even for a day or two, you must winterize. Most freeze damage we repair happens when someone shuts the furnace off for one cold night.
What happens if my RV freezes before I winterize it?
Freezing water expands and typically splits PEX fittings, the water pump head, the city water inlet, filter housings, low-point drains, and sometimes the water heater tank. Damage often stays hidden until you pressurize the system in spring and water floods a cabinet or the subfloor. If you suspect a freeze, have the system pressure tested before filling the tank.
Should I remove my RV batteries for winter storage?
Lead-acid batteries should be removed or fully disconnected, topped up with distilled water, and stored charged in a cool place with a maintainer — a discharged lead-acid battery can freeze and be destroyed. Lithium (LiFePO4) batteries should be stored around 50% state of charge and must not be charged below 0°C unless they have internal heating.
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