Winterizing has a reputation as a mysterious ritual, but it's really one core idea — water expands when it freezes, so get water out of everything — plus a handful of protection steps for the roof, tires, battery, and interior. An afternoon in the fall, and the rig sleeps safely until spring.
Part 1: Plumbing — the part that actually breaks
Nearly every freeze casualty we repair is plumbing: split lines, cracked pump heads, burst water heater fittings. The sequence:
- Drain everything. Empty and flush the black and gray tanks (a dose of tank treatment before the final flush leaves them clean for storage), then drain the fresh tank and open the low-point drains.
- Drain the water heater — after it's cool and with the pressure relieved. Pull the drain plug or anode rod. A shocking amount of freeze damage starts in a water heater someone forgot.
- Bypass the water heater. Most rigs have a bypass valve so you don't waste gallons of antifreeze filling a tank that's already empty. No bypass? A kit is cheap and installs once.
- Pump RV antifreeze through the lines. The pink, non-toxic RV antifreeze — never automotive — pumped through until every fixture runs pink: each faucet hot and cold, shower, outside shower, toilet, and low-point drains. Don't forget to pour a cup into each drain trap and the toilet bowl.
The alternative method: blowing the lines out with compressed air at low pressure, then antifreeze in the traps only. It works well when done thoroughly, but "thoroughly" is the catch — trapped water in a low spot is how "I blew out the lines" rigs still end up in our shop. If you're new to this, pink through every fixture is the method that fails safe.
Part 2: The roof check — winter's other attack
Snow sitting on a marginal sealant bead all winter is how spring water damage happens. Before storage, do the roof inspection from our roof leak guide: check every fixture and seam, and refresh anything questionable with self-leveling lap sealant while it's still warm enough to cure. Patch any actual damage with roof tape now — not in April when the ceiling stain announces it.
Part 3: Tires, battery, and fuel
- Tires: inflate to the sidewall maximum for storage, park on boards or pads rather than bare ground, and cover them — UV and sitting flat-spot tires faster than miles do.
- Battery: a battery left connected all winter drains, and a discharged battery freezes. Either disconnect and store it somewhere above freezing on a maintainer, or at minimum disconnect the ground.
- Fuel (motorhomes and generators): full tank plus stabilizer, then run the engine and generator long enough to move treated fuel through. Generators especially hate sitting with untreated fuel — spring carb cleanings keep our shop busy.
Part 4: The interior — against moisture and mice
- Remove every scrap of food. Mice smell what you forgot, and a mouse winter in an RV is a genuinely expensive event — they eat wiring insulation.
- Defrost the fridge, dry it, and prop the doors open. A closed damp fridge grows a science experiment.
- Set moisture absorbers in a couple of spots; trapped humidity is where storage mildew comes from. A wireless humidity monitor lets you check on the rig from your phone all winter.
- Wash and dry the exterior, then a coat of wash-and-wax so winter grime doesn't bond to the gelcoat. Cover it if you can — a breathable RV cover, not a plastic tarp, which traps moisture and scuffs the finish.
The spring payoff
A rig winterized like this de-winterizes in an hour: flush the pink out, sanitize the fresh system, reconnect the battery, check the roof, go camping. The rigs that skip this list spend spring in shops like ours instead — and the repair bill for one split fitting inside a wall buys a decade of antifreeze.
Everything mentioned is on our RV & Boat Repair and Must-Haves boards. Prefer it done for you? Winterizing and spring de-winterizing are services we offer — request a quote before the first freeze warning, when everyone calls at once.