Twelve skipped steps that cause real winter damage — each with its consequence and its fix.
Research — common mistakes compiled from manufacturer guidance and published owner experience. This page does not claim the author made any of these mistakes.
Most cold-weather RV damage is not bad luck — it is a step skipped, a product swapped, or a "that'll be fine" that wasn't. Each mistake below lists its real consequence and its fix. Severity tags are a rough guide: High means it can cause major damage or a big repair bill; Medium means it shortens equipment life or causes a moderate repair.
Before reading the whole list, run this check. Every "no" points to a mistake below.
Consequence: pump antifreeze without setting the bypass, and you fill a 6- or 10-gallon tank with antifreeze you then have to flush out in spring — wasted product and a long flush job, and diluted antifreeze everywhere else if you ran short.
Fix: set the bypass first, then pump. If you already filled the tank, drain it, flush thoroughly in spring, and check the anode rod while you're there. Full steps: winterizing checklist.
Consequence: everyone remembers the kitchen faucet. The outside shower, the toilet valve, and the low-point drains are the ones that get missed — and they are the ones that split, leaking inside walls where you won't find the damage until spring.
Fix: run antifreeze through every outlet, including the ones you never use, until each runs pink. Work from a written list of outlets, not from memory.
Consequence: automotive antifreeze is toxic and is not made for potable water systems. Getting it into drinking lines is a serious contamination problem, not a minor mix-up.
Fix: RV antifreeze is non-toxic and pink, made for this exact job. They are not interchangeable. If automotive antifreeze ever gets into the lines, flush the system thoroughly before anyone drinks from it — and if in doubt, have it checked professionally.
Consequence: detectors, radios, and control boards draw a little power all the time. Over months, "a little" becomes a dead, possibly frozen and cracked battery — and a frozen battery is usually scrap, not a recharge job.
Fix: disconnect, maintain, or pull them — full guide: What to do with RV batteries over winter. And check monthly either way: disconnecting stops parasitic loads, not self-discharge.
Consequence: closing every vent to "keep the cold out" traps moisture inside, and moisture grows mildew all winter — on cushions, in cabinets, behind walls. Mildew remediation is miserable work.
Fix: leave some ventilation, crack cabinet doors, leave the fridge door ajar, and consider moisture absorbers. Check inside monthly.
Consequence: tires lose roughly 1 PSI per 10°F drop, and a soft tire sitting in one spot all winter can flat-spot. UV ages rubber even in winter, shortening tire life.
Fix: inflate to sidewall pressure before storage, cover tires that sit in sun, and move the rig occasionally if you can.
Consequence: grit under a cover grinds the finish all winter, so washing matters. And a cover that blows loose is worse than useless — it flaps and abrades. Skipping the cover entirely leaves the roof and seals to take the full winter.
Fix: wash and dry before covering, strap it down underneath (not just at the hem), and check it after storms. Guide: RV cover buying guide.
Consequence: winterizing is not one-and-done. A cover worked loose in a storm, a battery quietly dying, a slow leak — all of them get worse for months unnoticed, and all of them are cheap to catch early.
Fix: a monthly check — cover secure, batteries charged, no water where it shouldn't be, no mice — catches small problems before they become spring repair bills.
Consequence: a propane furnace needs 12-volt power for its fan and controls. If the batteries die, the furnace stops, and then the pipes are unprotected. This is how "I left the heat on" ends with burst pipes anyway.
Fix: heat and battery care are one system in winter, not two separate jobs. If you rely on heat, you must also guarantee power and propane for the whole winter — or winterize properly and stop relying on heat at all.
Consequence: extended slide-outs collect snow loads on their roofs, their seals sit compressed and exposed to freeze-thaw, and snowmelt can find its way in around the seals. Awnings left out in winter have the same problem, worse.
Fix: bring slide-outs in for storage unless your manual says otherwise, and never leave awnings extended through winter weather. If a slide must stay out, keep snow cleared off its roof and check the seals monthly.
Consequence: the water pump and its inlet strainer hold water even after the lines are drained. That trapped water freezes, cracks the pump head or strainer bowl, and you discover it as a leak on the first spring trip.
Fix: run the pump briefly while winterizing so antifreeze passes through it, and drain the strainer bowl. If your pump has a winterizing kit, use it — that's what it's for.
Consequence: tarps don't breathe, so moisture condenses underneath and grows mildew; they have no soft lining, so they abrade the finish in wind; and they have no shaped fit, so they billow and tear. The "cheap" cover often costs more in finish damage than a real cover would have.
Fix: a breathable RV cover sized to your measured length, strapped underneath, checked after storms. See the cover guide.
Every rig differs — bypass valve locations, drain points, battery setups, tankless heater procedures. The owner's manual for your exact model beats any general checklist, including this one. Use the checklist to make sure nothing is missed, and the manual to do each step right. This isn't a thirteenth mistake so much as the one that causes the other twelve.
The pattern: nearly every mistake on this list is a skipped step, not a hard job. Slow down, work the checklist in order, and check on the rig through the winter.
What's the single most expensive first-timer mistake?
Water left somewhere it shouldn't be — usually the outside shower, toilet valve, or a missed low-point drain. Burst pipes and the water damage they cause inside walls are the biggest winter repair bills, and they come from one skipped outlet.
Winterized late, after a freeze — is the damage already done?
Not necessarily — one mild frost doesn't always split a fitting, but a hard freeze with water in the lines very well may. Winterize now anyway (it stops further damage), then pressure-test the system in spring before your first trip: pressurize, watch for leaks, and check every fixture and low point.
Can I fix a mistake mid-winter?
Mostly yes. A missed outlet can still be antifreezed on a warmer day; a loose cover can be re-secured; a dying battery can be charged or pulled. The mistakes that can't be fixed mid-winter are the ones you don't know about — which is why the monthly check matters more than a perfect October.
Does insurance cover winterizing mistakes?
Often not — many policies exclude damage from failure to winterize, or require winterizing by a certain date. Check your policy's fine print before winter, not after a claim. This page isn't insurance advice; your policy is the document that counts.