How to Winterize Your RV: A Step-by-Step Guide to Cold Storage

Why Winterization Matters

A single overnight freeze at 28°F is enough to split a water pump housing — and most RV water pumps sit completely exposed under the floor with zero insulation. Water expands roughly 9% when it freezes, and plastic fittings, aluminum pipe joints, and pump housings don't have that kind of give. The result is typically cracked components that can run anywhere from a few hundred dollars into several thousand to repair, depending on how much of your plumbing system gets hit.

Winterization typically takes an afternoon and a few supplies. Skipping it is a gamble most full-timers and seasonal RVers won't take twice.

When to Winterize — and It Depends Where You Are

Northern tier states (Minnesota, Michigan, Wisconsin, Montana, the Dakotas): Start watching the forecast in late September. Overnight lows below freezing often arrive by mid-October. If your rig will sit unheated even one night below 32°F, it's time. Many northern RVers winterize by Columbus Day weekend as a rule of thumb.

Mid-Atlantic and Midwest (Pennsylvania, Ohio, Illinois, Missouri): October–November is typical. You often get a longer window, but a surprise early freeze in late October is common enough that waiting until Thanksgiving is a risk.

Southwest and Sun Belt (Arizona, New Mexico, Southern California): Many RVers in Tucson or the Phoenix area skip winterization entirely — or only partially winterize if they're leaving the rig parked at elevation (Flagstaff at 7,000 feet sees hard freezes regularly). If you're staying in the low desert and the rig stays heated, you may be fine. But if it's parked and unmonitored even in the Southwest, winterize it.

Bottom line: winterize when consistent overnight temperatures drop below 32°F and your RV will sit unused. Better to do it a week early than the morning after a freeze.

What You'll Need

• RV antifreeze (non-toxic pink antifreeze — not automotive antifreeze, which is toxic) — most Class A and fifth-wheels need 2–3 gallons; smaller Class B and C rigs often get by with 1–2 gallons
• Water pump converter kit or inline pump bypass (Camco's blow-out plug kit and pump converter kits are the go-to at most Camping World, Ace Hardware, or Amazon; search "Camco 36543" for the converter kit)
• Compressed air blowout plug — a $10–$15 fitting that screws onto your city water inlet; Camco and Valterra both make reliable ones
• Air compressor capable of 30–50 PSI (a small pancake compressor like the California Air Tools 2010A works fine — you don't need a shop compressor)
• Water heater bypass kit (if not already installed — most rigs built after 2010 have one factory-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. Downside: the pink antifreeze taste and smell can linger until you flush thoroughly in spring. Most RVers I know who've been doing this more than a few years stick with the antifreeze method purely for peace of mind.

Compressed air blowout: Air is forced through each line to push out standing water. Faster than antifreeze, leaves no residue. Downside: you need a compressor and must stay at or below 50 PSI — higher pressure can damage plastic fittings. Low spots in the plumbing can retain water pockets the air misses entirely. Not recommended as your only method on complex systems with multiple slide-outs or a residential-style plumbing layout.

Step-by-Step Winterization Process

1. Drain the fresh water tank. Open the low-point drains (typically under the RV on each side) and drain completely. Leave them open while you work.
2. Drain and bypass the water heater. Never pump antifreeze through the water heater — it wastes antifreeze and isn't necessary. Use the bypass valve to isolate the heater. Remove the exterior drain plug (usually an anode rod plug on the lower corner of the heater door) and let it drain fully. A water heater that doesn't drain completely is a common freeze point people miss.
3. Drain the black and gray tanks. Both tanks should be emptied and flushed before storage. Run the tank rinse system if your rig has one. Storing a half-full black tank over winter is asking for a bad spring.
4. Pump antifreeze through the system. Use the converter kit to draw antifreeze directly from the jug into the water pump inlet. Turn on the pump and open each faucet — hot side first, then cold — until you see pink antifreeze flowing steadily. Hit every faucet, the outdoor shower, toilet, and any ice maker or washing machine lines if equipped.
5. Pour antifreeze in each drain. A small amount (a cup or so) in each sink drain, shower drain, and toilet keeps the P-traps from freezing. This step gets skipped more than any other, and it's the one that bites people when a bathroom sink trap cracks over winter.
6. Flush the toilet. Pour antifreeze directly into the bowl and actuate the flush valve until pink water appears in the toilet mechanism.

Beyond Plumbing: The Rest of Winterization

Battery maintenance: Disconnect and store batteries in a cool, frost-free location — a basement or heated garage works well. A smart trickle charger like the NOCO GENIUS5 will keep them at optimal charge all winter without overcharging. A fully discharged lead-acid battery in sustained freezing temperatures can freeze internally and fail permanently.

Refrigerator: Empty, defrost, and prop the door open slightly to prevent mold. Leave a box of baking soda inside to absorb odors. If your fridge has a power-vent mode, disable it — no reason to run it empty all winter.

Propane: Turn off propane tanks at the valve. Many RVers remove tanks and store them in covered outdoor storage. Protect regulators and hose connections from moisture and UV — cracked regulator diaphragms are a common spring surprise.

Roof and seals: Inspect all roof seams and seals before storage and reseal any cracked sections with a compatible lap sealant (Dicor self-leveling for flat sections, non-sag for vertical). Water intrusion over a winter with freeze-thaw cycles causes far more damage than the cold itself. A $15 tube of Dicor now beats a $2,000 ceiling repair in May.

Slide-outs: Retract all slide-outs for storage to minimize seal exposure and reduce stress on the extension mechanism over months of non-use.

Tires: If storing long-term, place the RV on leveling blocks or Lynx stacker blocks to take weight off the tires. At minimum, inflate to the maximum sidewall pressure and add tire covers — UV degradation over winter causes more sidewall cracking than cold temperatures do.

Rodent exclusion: Mice find unoccupied RVs irresistible in winter. Stuff steel wool (not fiberglass — it compresses too easily) into any penetrations under the rig: water lines, wire conduits, exhaust vents. Dryer sheets placed inside have mixed reviews, but many RVers swear by them. Victor's electronic repellers work well in enclosed spaces. Check and seal any gaps in underbelly insulation — even small ones.

Spring De-Winterization

In spring, reconnect batteries, remove the water heater bypass, reinstall the drain plug, and flush all lines with fresh water until the antifreeze is gone. Plan on running two or three full fresh-water tanks through the system before you'd want to drink from it. Check all seals for winter shrinkage, recheck tire pressure (cold winter temperatures drop PSI noticeably), and test all propane connections with soapy water before heading out on your first trip.

Related: RV maintenance checklist  ·  RV tire safety guide  ·  RV propane safety guide