How to Winterize an RV: Protecting Your Home on Wheels from Freezing Temperatures

The first time I watched water expand and crack a neighbor's RV pipes, I understood viscerally why winterization isn't just another maintenance task—it's an act of preservation. That was fifteen years ago in northern Michigan, and the sound of those pipes splitting still echoes in my mind every October when the leaves start turning.

Winterizing an RV is fundamentally about preventing water from destroying your investment. But it's also about something deeper: respecting the physics of freezing water and understanding your RV as a complex system of interconnected vulnerabilities. I've winterized dozens of RVs over the years, from vintage Airstreams to modern Class A motorhomes, and each one taught me something new about where water hides and how cold finds its way in.

The Philosophy of Water Management

Before diving into the nuts and bolts, let's talk about water's personality. When water freezes, it expands roughly 9% in volume. This seemingly small percentage translates to tremendous force—enough to split copper pipes, crack plastic fittings, and destroy water pumps that cost more than your monthly mortgage payment. Your RV's plumbing system wasn't designed to withstand this expansion. It was designed for flow, not ice.

I learned this lesson the hard way during my second winter of RV ownership. Despite following what I thought was a thorough winterization process, I'd missed the outdoor shower line. Come spring, I discovered a $400 mistake hidden behind an access panel. That failure taught me that winterization isn't about following a checklist—it's about understanding every place water travels in your specific RV.

Timing Your Winterization

The question of when to winterize reveals a lot about an RV owner's relationship with risk. Some folks wait until the first hard freeze warning. Others, particularly full-timers heading south, might never winterize at all. I've found the sweet spot is when nighttime temperatures consistently dip below 40°F. This gives you a buffer before the real danger zone of 32°F.

But here's something most people don't consider: partial winterization. If you're still using your RV during shoulder seasons, you can winterize just the exterior components while keeping the interior systems functional. I discovered this approach during a particularly mild winter when I wanted to take occasional weekend trips but couldn't risk freeze damage during the week.

The Antifreeze Debate

Let me address the elephant in the room: RV antifreeze. The pink stuff. Some swear by it, others insist compressed air is sufficient. After years of experimentation, I've landed firmly in the "both" camp, though not necessarily at the same time.

RV antifreeze—specifically the non-toxic, propylene glycol variety—offers peace of mind that air alone cannot. It physically occupies the space where water would otherwise lurk. But here's what the forums don't tell you: antifreeze has a personality too. It's slightly viscous, leaves a aftertaste that haunts your water system come spring, and has an uncanny ability to find its way into places you didn't know existed.

The compressed air method appeals to the minimalist in me. It's clean, requires no chemicals, and forces you to truly understand your RV's plumbing layout. But air doesn't protect against condensation, and it certainly doesn't help if you missed a low spot where water naturally collects.

The Actual Process (With Hard-Won Insights)

Start with the water heater. This six or ten-gallon tank is your biggest vulnerability and, ironically, the easiest to protect. Turn off the heater—both electric and propane if you have both—and let it cool completely. I once made the mistake of draining a hot water heater and watched in horror as the cold water inlet caused the tank to warp slightly. No permanent damage, but a lesson in thermal dynamics I won't forget.

Open the pressure relief valve first, then remove the drain plug. Here's a detail that matters: that drain plug probably has an anode rod attached. Inspect it. If it looks like a piece of chalk that's been left in acid, replace it. This sacrificial rod protects your tank from corrosion, and winter is the perfect time for this five-minute maintenance task.

The freshwater tank comes next, and this is where RV design varies wildly. Some have easily accessible low-point drains. Others seem designed by someone who actively despised future owners. My current RV requires me to crawl under the vehicle to access the freshwater drain. I've learned to do this job on a warm autumn day, not when the ground is frozen and my joints are protesting.

Now for the controversial part: I don't just drain my freshwater tank. I sanitize it first. A quarter cup of bleach per 15 gallons of water, run through the entire system, then thoroughly flushed. Why? Because biofilm—that slimy coating that develops in stagnant water—thrives in the moist environment of a partially drained tank. Come spring, you'll thank yourself for this extra step.

The Hidden Water Traps

Every RV has them—places where water collects and hides like a fugitive from justice. The toilet valve seal holds about a cup of water. The water pump itself contains residual water even after the system is drained. My personal nemesis: the outside shower. Even when you think it's drained, there's always a low spot in the line where water pools.

Ice makers are another modern convenience that becomes a winter liability. If your RV has one, the water line needs to be disconnected and drained. I learned this from a fellow RVer who discovered a split line had leaked all winter, resulting in extensive floor damage. Now I remove the entire ice maker if possible, storing it inside for the winter.

Don't forget about the washing machine if you have one. These appliances have internal water that doesn't drain completely through normal use. Run a cycle with antifreeze, or better yet, remove and store it where it won't freeze.

The Bypass Ballet

Installing a water heater bypass kit was the best $20 I ever spent on winterization. Without it, you're pouring antifreeze into a six-gallon tank just to protect the handful of pipes connected to it. That's wasteful and expensive. The bypass allows you to isolate the water heater and protect just the plumbing lines.

But here's what nobody mentions: bypass valves can fail. They're simple devices, but the rubber seals deteriorate over time. I check mine every fall by pressurizing the system with air and listening for leaks. A failed bypass valve means antifreeze in your water heater come spring—not catastrophic, but certainly annoying.

The Antifreeze Method (If You Choose It)

If you're going the antifreeze route, buy more than you think you need. The general rule is 2-3 gallons, but I've used up to 5 gallons in larger RVs with washing machines and ice makers. Don't cheap out here—RV antifreeze is specifically formulated to be non-toxic and safe for plumbing systems. Automotive antifreeze will kill you.

Start by closing all drains and installing drain plug caps on the low-point drains. Connect the antifreeze intake hose (usually near the water pump) to your first gallon. Turn on the water pump and open each faucet—hot and cold separately—until pink antifreeze flows steadily. Don't forget the toilet, outdoor shower, and any other water outlets.

Here's a pro tip: after running antifreeze through the toilet, pour an extra cup directly into the bowl. This protects the seal and prevents sewer gases from entering your RV over the winter.

The Compressed Air Alternative

The compressed air method requires an air compressor, a blow-out plug that fits your city water inlet, and patience. Set your compressor to 30-40 PSI—no higher, or you risk damaging seals and fittings. Higher pressure doesn't equal better winterization; it equals expensive repairs.

Connect the blow-out plug and introduce air into the system. Open each faucet starting with the one closest to the inlet, allowing air to force water out. You'll hear gurgling, spitting, and what sounds like an angry dragon—this is normal. Keep each faucet open until only air comes out, then move to the next.

The challenge with air is ensuring you've removed water from every low point. I supplement this method by pouring a cup of antifreeze down each drain to protect the P-traps. It's a hybrid approach that combines the cleanliness of air with the protection of antifreeze where it matters most.

Beyond the Plumbing

Winterization extends beyond just the water system. Your RV's batteries need attention too. A fully charged battery can survive freezing temperatures, but a discharged one will freeze and crack. I remove my batteries entirely, storing them in my garage on a battery tender. If you must leave them in the RV, disconnect the negative terminal to prevent parasitic draws.

Propane appliances need love too. Insects and spiders view your furnace exhaust and water heater vents as perfect winter homes. Their nests can block proper ventilation, creating dangerous conditions come spring. I cover these vents with screens or approved vent covers, making a note to remove them before the first use.

Speaking of unwanted guests, mice consider your RV a winter resort. They'll chew through walls, nest in your insulation, and leave calling cards everywhere. I've tried every deterrent imaginable—dryer sheets, Irish Spring soap, peppermint oil, ultrasonic devices. The only thing that consistently works is sealing every possible entry point with steel wool and expanding foam, then setting traditional traps as backup.

The Forgotten Systems

Your RV's refrigerator needs attention whether it's staying in the RV or not. If leaving it in place, clean it thoroughly, prop the doors open, and place baking soda inside to absorb odors. For absorption refrigerators, check that the cooling unit is level—storing an RV on an incline all winter can damage these sensitive systems.

The air conditioning system often gets overlooked during winterization. While it won't freeze, covering the exterior unit prevents debris accumulation and UV damage. I use a breathable cover that allows moisture to escape while keeping leaves and snow out.

Don't forget about your RV's waste system. After dumping and flushing the black and gray tanks, I add a few gallons of antifreeze to each. This prevents any residual water from freezing and keeps the valve seals lubricated. Some folks swear by leaving the valves open all winter, but I've seen too many dried-out seals to recommend this approach.

Storage Considerations

Where you store your RV matters almost as much as how you winterize it. Covered storage protects against UV damage and reduces snow load on the roof. But it also tends to trap moisture, potentially leading to mold and mildew issues. I prefer outdoor storage with a breathable RV cover, visiting monthly to check for issues and ensure ventilation.

Before storage, wash and wax your RV. Road grime and bird droppings become increasingly corrosive over time. Pay special attention to the roof—pooling water that repeatedly freezes and thaws can work its way into the smallest cracks, causing extensive damage.

Tire care during storage is often overlooked. Inflate tires to the maximum recommended pressure to compensate for cold weather pressure loss. If possible, park on boards rather than directly on ground or concrete to prevent flat spots. Some dedicated RVers jack up their rigs and remove the tires entirely, but I find this overkill for typical winter storage.

The Spring Awakening

De-winterization is winterization in reverse, but with its own quirks. If you used antifreeze, you'll need to flush the system thoroughly. I mean thoroughly—that pink taste has a way of lingering like a bad houseguest. Run fresh water through every line until you can't detect any trace of antifreeze, then sanitize the entire system with bleach solution.

Check every fitting and connection for leaks. The freeze-thaw cycle can loosen connections that were tight in the fall. Run water through the system at full pressure and inspect carefully. Finding a leak in your driveway beats discovering it at a campground 500 miles from home.

Final Thoughts

Winterizing an RV is ultimately about respect—respect for the power of freezing water, respect for your investment, and respect for the adventures that await when warm weather returns. Each RV is different, with its own quirks and vulnerabilities. The process I've described works for most, but your RV might have unique features requiring additional steps.

The first time you winterize your RV, budget extra time. Take photos of valve positions, make notes about which faucets drain slowly, and document any challenges you encounter. This record becomes invaluable for future winterizations and for troubleshooting problems come spring.

Remember, winterization isn't just about preventing damage—it's about peace of mind. When January's polar vortex drops temperatures to levels that make polar bears shiver, you'll sleep better knowing your RV is protected. And when spring arrives and you're ready for that first camping trip, you'll appreciate the time invested in proper winterization.

The sound of water flowing freely through your RV's pipes after a successful de-winterization is one of the most satisfying sounds in the RVing world. It means you did it right. It means adventure awaits. And it means you've mastered one of RVing's essential skills.

Authoritative Sources:

Woodall's RV Owner's Handbook. Woodall's Publications Corp, 2019.

National Fire Protection Association. "NFPA 1192: Standard on Recreational Vehicles." National Fire Protection Association, 2021.

Recreation Vehicle Industry Association. RV Repair and Maintenance Manual. Trailer Life Books, 2020.

U.S. Environmental Protection Agency. "Drinking Water Contaminants – Standards and Regulations." EPA.gov, 2021.

Moeller, Bill, and Jan Moeller. RV Repair & Maintenance Manual. McGraw-Hill, 2018.