Why Winterization Matters
Water expands when it freezes. Any water left in your RV's plumbing system — pipes, water pump, water heater, holding tanks, ice maker lines — can freeze and split components that cost hundreds or thousands of dollars to replace. Winterization takes 2–4 hours and a few supplies. Skipping it is a gamble that costs most people who lose it $500–$3,000 in repairs.
When to Winterize
Winterize when consistent overnight temperatures drop below 32°F and your RV will sit unused. In northern states, that's typically October–November. If you're still using the RV, you can hold off — but the moment it sits unheated overnight with freezing forecast, you're at risk. Better to winterize a week early than the morning after a freeze.
What You'll Need
- RV antifreeze (non-toxic pink antifreeze, not automotive) — 2–3 gallons for most rigs
- Water pump converter kit (or a bypass kit already installed)
- Compressed air (optional — for blowout method)
- Water heater bypass kit (if not already installed)
- Basic hand tools for access panels
The Two Methods: Antifreeze vs. Compressed Air
Antifreeze method: The most common approach. RV-specific pink antifreeze is pumped through all water lines. It's reliable, doesn't require special equipment, and leaves lines protected even if you miss pockets. Downsides: the pink antifreeze taste/smell lingers until the spring flush. Some RVers dislike introducing it to the water system.
Compressed air blowout: Air is forced through each line to push out standing water. Faster than antifreeze, leaves no residue. Downsides: requires an air compressor and proper regulator (max 50 PSI — too much pressure damages plastic fittings). Pockets of water in low sections can be missed. Not recommended as the sole method for complex plumbing systems.
Best practice: Use the air blowout to remove most water, then follow with antifreeze to protect any remaining moisture in traps and low spots.
Step-by-Step Winterization Process
- Drain the fresh water tank. Open the low-point drains (typically under the RV) and drain completely. Leave them open while working.
- Drain and bypass the water heater. Never pump antifreeze through the water heater — it wastes antifreeze and isn't necessary. Use the bypass valve (or bypass kit) to isolate the heater. Remove the drain plug to fully drain the tank.
- Drain the black and gray tanks. Both tanks should be emptied and flushed before storage. Run tank rinse systems if equipped.
- Pump antifreeze through the system. Use a converter kit to draw antifreeze directly from the jug into the water pump. Turn on the pump and open each faucet — hot and cold separately — until you see pink antifreeze flowing. Do every faucet, the outdoor shower, ice maker line, and washing machine line if equipped.
- Pour antifreeze in each drain. A small amount in each sink drain, shower drain, and toilet keeps the P-traps protected.
- Flush the toilet. Run antifreeze through the toilet flush until pink water appears.
Beyond Plumbing: The Rest of Winterization
Battery maintenance: Disconnect and store batteries in a cool, frost-free location. A smart trickle charger or battery maintainer will keep them at optimal charge over winter. A fully discharged battery in freezing weather can fail permanently.
Refrigerator: Empty, defrost, prop the door open slightly to prevent mold. Leave a box of baking soda inside to absorb odors.
Propane: Turn off propane tanks at the valve. Many RVers remove and store tanks separately in covered outdoor storage. Regulators and hose connections should be protected from moisture.
Roof and seals: Inspect all roof seams and seals before storage and reseal any cracked sections. Water intrusion over winter causes far more damage than the cold itself.
Slide-outs: Retract all slide-outs for storage to minimize seal exposure and weight on the extension mechanism over months of storage.
Tires: If long-term storage, place the RV on leveling blocks to take weight off the tires, or at least inflate to max sidewall pressure. Consider tire covers to prevent UV degradation.
Rodent exclusion: Mice find RVs irresistible in winter. Stuff steel wool in any penetrations under the RV. Place fabric softener sheets or mouse repellent inside. Check and seal any gaps in underbelly insulation.
Spring De-Winterization
In spring, reconnect batteries, remove the water heater bypass, install the drain plug, and flush all lines with fresh water until the antifreeze smell is gone. Run 2–3 fresh tanks through the system before drinking. Check all seals, recheck tire pressure, and test propane connections before heading out.
Related: RV maintenance checklist · RV tire safety guide · RV propane safety guide
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