How to Winterize an RV: The Complete Step-by-Step Guide

In RV service shops across the country, mechanics have a name for what happens every March and April. They call it the spring rush. Owners pull into the service bay one after another with the same story: opened up the rig for the season, turned on the water pump, heard water running where it shouldn't.

The damage pattern is consistent. A cracked PEX line behind an exterior wall. A split fitting under the floor. A water heater tank that fractured during a hard freeze and won't show its damage until the owner fills it for the first time. By the time interior paneling, flooring, insulation, and mold remediation are accounted for, the repair runs $1,500 to $3,000. The rig sits in the shop for three to six weeks. Insurance covers some of it, depending on the policy and the deductible. The owner pays the rest and writes off the early-season trips they'd planned.

The frustrating part is that this is one of the most preventable failure modes in RV ownership. Winterizing an RV is not a complicated procedure. It takes an afternoon, costs about thirty dollars in supplies, and protects against thousands of dollars in damage. The hard part isn't doing the work. The hard part is knowing exactly what your specific rig needs.

This guide walks through every step.

When to Winterize

The simple rule: winterize before the first night your stored RV will drop below freezing. Not the first forecasted freeze. The first actual freeze. Weather services are wrong often enough that "I'll do it next weekend" is how rigs get damaged.

For most of the country, that means starting the conversation in early to mid October. In the northern states and Canada, late September. In the Mountain West, it depends entirely on elevation and can mean September at higher altitudes. In the Deep South and the Southwest, you may only need to winterize partially or not at all, depending on whether your storage location reliably stays above freezing.

"Winterizing a week early costs you an afternoon. Winterizing a week late can cost you thousands."

The principle is asymmetric risk. Winterizing a week early costs you an afternoon. Winterizing a week late can cost you thousands. There's no version of this where erring early is the wrong call.

A note on regional variation: if you store your RV in a heated facility or a climate-controlled garage, you don't need to winterize at all, provided the storage stays consistently above 35 degrees. If your storage is outdoors and unheated, the rules in this guide apply regardless of how mild your region is. A single hard freeze is enough.

What You'll Need

Plan to spend about $30 to $50 on supplies for the first winterization. You'll have some of these on hand in future years.

Required:

• Two to three gallons of non-toxic RV antifreeze (the pink stuff, propylene glycol). Larger rigs may need four gallons.
• A water heater bypass kit if your rig doesn't already have one installed (most newer rigs do).
• A blow-out plug for the city water inlet, OR a water pump converter kit, depending on which winterizing method you use.

Strongly recommended:

• A bucket or pan to catch drained water.
• A wrench for the low-point drain valves (size varies by rig).
• A flashlight for checking under cabinets and in storage bays.

Optional but useful:

• A small air compressor if you plan to blow out the lines instead of using antifreeze.
• RV-specific antifreeze for waste tanks, separate from plumbing antifreeze.

A note on antifreeze: use only RV antifreeze, never automotive antifreeze. Automotive antifreeze is ethylene glycol, which the CDC's Agency for Toxic Substances and Disease Registry identifies as a substance that can damage the kidneys, nervous system, lungs, and heart with significant exposure. It would contaminate your water system permanently. RV antifreeze is propylene glycol, classified as low-toxicity and used in food and beverage processing, cosmetics, and pharmaceuticals.

The Core Winterizing Process

The sequence below works for most RVs. Specific steps may vary slightly based on your rig's plumbing layout, so check your owner's manual if you're unsure where a specific component lives on your rig.

Step 1: Drain the Fresh Water System

Start by draining the fresh water tank completely. Most rigs have a dedicated drain valve underneath; open it and let the tank empty. While that's draining, open every faucet in the rig (hot and cold sides), the shower, the outdoor shower if you have one, and the toilet flush. This relieves pressure and lets the system drain fully.

Don't forget the ice maker line if your rig has a refrigerator with an ice maker. This is one of the most commonly missed components and a common source of freeze damage.

Step 2: Bypass and Drain the Water Heater

The water heater is the single most expensive component to damage from freezing. A cracked tank means replacing the entire water heater, often $400 to $800 for the unit plus installation.

"The water heater is the single most expensive component to damage from freezing."

Engage the bypass valves on your water heater (most newer rigs have these factory-installed; older rigs may need a bypass kit added). Then open the drain plug on the water heater itself and let it drain completely. A six-gallon tank takes a few minutes; ten-gallon tanks longer.

Important: never add antifreeze to a water heater. Suburban (one of the two dominant RV water heater manufacturers) explicitly recommends bypassing the unit before introducing antifreeze, because antifreeze is corrosive to the anode rod and causes accelerated deterioration and heavy sediment buildup. If you skip the bypass and pour antifreeze through the system, you'll also fill the tank with $50 worth of antifreeze that you then have to drain. The bypass routes antifreeze around the heater entirely.

Step 3: Drain Low Points and Waste Tanks

Locate your low-point drains. Most rigs have two (one for hot water lines, one for cold), usually accessible from underneath the rig. Open them and let any remaining water drain out.

While you're underneath, empty the gray and black tanks at a dump station if they aren't already empty. Standing water in waste tanks can freeze and damage the tank or valves.

Step 4: Add Antifreeze (or Blow Out the Lines)

You have two options here, and RVers debate which is better. Both work if done correctly.

Option A: Antifreeze method. Connect a water pump converter kit (a short hose that bypasses the fresh water tank and lets you draw antifreeze directly from a jug). Place the intake end into your first jug of antifreeze. Turn on the water pump. Then, starting with the faucet farthest from the pump, open hot and cold sides one at a time until pink antifreeze flows steadily from each. Move to the next faucet. Continue through every fixture: kitchen sink, bathroom sink, shower, outdoor shower, toilet. Switch jugs as needed.

Option B: Blow-out method. Use a blow-out plug connected to a small air compressor at the city water inlet. Keystone RV, one of the largest RV manufacturers, recommends setting air pressure to no more than 30 PSI; higher pressures risk damaging fittings and plumbing joints. With faucets open one at a time, blow air through each line until no more water comes out. Some RVers prefer this because no antifreeze residue lingers in the lines.

Most RV manufacturers and most owners use the antifreeze method because it's harder to miss something. The blow-out method requires more attention to ensure every line is fully cleared. If you're new to winterizing, use antifreeze.

Step 5: Antifreeze Through Drains and Traps

Pour a cup of RV antifreeze down each sink drain, the shower drain, and the toilet. This protects the P-traps from freezing and cracking. Also pour about a cup directly into the toilet bowl after flushing to protect the toilet seal and any water sitting in the flush valve.

Step 6: Final Checks

Walk through the rig and verify:

• All faucets are closed
• Water pump is turned off
• Water heater bypass is engaged
• Low-point drains are closed (some RVers leave them open through winter, which is also valid)
• Fresh water tank drain is closed
• All exterior compartments are dry

You're done with the plumbing.

Rig-Type Specifics

Most of the steps above apply to all RV types. A few rig-specific considerations:

Motorhomes (Class A, B, and C): Pay attention to the engine cooling system on gas models. The engine antifreeze should be checked or replaced on its own schedule, separately from plumbing winterization. Diesel pushers and motorhomes with onboard generators may have additional winterizing steps for the generator's cooling and fuel systems; consult your owner's manual.

Travel trailers and fifth wheels: These are the most straightforward to winterize because they don't have engine systems to worry about. Pay attention to outdoor kitchens and exterior shower fixtures, which are sometimes forgotten because they're not in the main living space.

Truck campers: Smaller water systems mean less antifreeze needed but the same procedure. Pay attention to the water heater location, which varies more than in larger rigs.

Pop-ups and hybrids: If your rig has soft sides, the canvas should be completely dry before closing for winter to prevent mold. Some owners also use a moisture absorber inside. Plumbing systems on pop-ups are simpler but follow the same drain-and-protect logic.

Beyond the Plumbing

Water lines are the biggest risk, but winterizing isn't only about water.

Batteries: Cold reduces battery life dramatically. Either disconnect the batteries entirely and store them somewhere warm (a garage works), or leave them connected to a trickle charger that maintains them through winter. If you do nothing, expect to replace batteries every two to three years instead of every five to seven.

Tires: Cover tires to protect from UV damage during long storage. If possible, park on wood or rubber pads rather than directly on cold concrete or asphalt, which can cause flat spots. Inflate to the maximum recommended pressure for storage; tires lose pressure in cold weather.

Interior: Rodents are the biggest threat. They chew through wiring, insulation, and fabric, often causing more damage over a winter than any other single issue. Use peppermint oil packets, dryer sheets in cabinets and drawers, or commercial rodent deterrents. Some RVers leave small lights on a timer to discourage nesting.

Moisture is the second interior threat. Use moisture absorbers (DampRid or similar) in bathrooms, closets, and storage bays. A small amount of mold prevention now is much cheaper than mold remediation in spring.

Exterior: The cover question divides RVers. Some swear by a quality RV cover; others argue covers trap moisture and abrade the finish. Either choice is defensible if done well. If you cover, use an RV-specific cover that breathes; never use a tarp. If you don't cover, do a thorough roof inspection before storage (cracked sealant becomes much worse over winter) and consider a wash and wax in the fall to protect the gel coat.

If you haven't inspected your roof recently, our guide on how to inspect your RV roof walks through what to look for.

Propane: Close the main propane valve at the tank. Inside the rig, ensure all propane appliances are off. Some owners disconnect the propane tanks entirely for the off-season; this is optional but reduces risk.

Common Mistakes to Avoid

After the plumbing process, here's where most owners go wrong:

Forgetting the ice maker line. Refrigerators with ice makers have a separate water line that's easy to miss. Run antifreeze through it (some models have a dedicated procedure in the manual) or blow it out.

Not bypassing the water heater. Filling a six-gallon water heater with antifreeze wastes $50 in antifreeze and requires a tedious drain-and-flush in spring. Always bypass.

Skipping the outdoor shower. Easy to forget because it's not in your daily-use mental model. Run antifreeze through both hot and cold sides.

Leaving the water pump on after antifreeze is added. Once you've filled the lines, turn the pump off. Otherwise it may continue to draw and cycle, eventually running dry or causing pressure issues.

Missing low-point drains. These are tucked underneath and easy to overlook. Both hot and cold side need to be drained.

Skipping antifreeze in drain traps. The P-traps under sinks and showers hold water that will freeze and crack the trap. A cup of antifreeze in each drain takes thirty seconds and prevents real damage.

"The most common winterizing mistake isn't doing it wrong. It's doing it almost right."

The most common winterizing mistake isn't doing it wrong. It's doing it almost right. Missing one line, one drain, or one trap is enough to cost you the spring.

What About Full-Timers?

If you live in your RV through the winter, the rules change. You're not winterizing for storage; you're winterizing for use in cold conditions, which is a different problem.

The key distinction: a stored, winterized RV has no water in the lines, so freezing is prevented by absence. A full-time RV in winter has water in the lines constantly, so freezing is prevented by warmth and insulation.

Skirting is the single most important investment for cold-weather full-timing. Skirting closes off the open space underneath your rig, where pipes and tanks live. Without skirting, the underside of your rig is essentially outdoor temperature, and pipes will freeze even with interior heat running. Skirting can be commercial vinyl panels, foam board, hay bales, or even tarps; the principle is enclosing the underside to trap warmth from the rig above.

Heated water hose is essential if you're connected to city water. A standard water hose freezes solid in a single cold night. A heated water hose (with built-in heating element) stays liquid down to roughly -40 degrees.

Tank heaters are electric pads that attach to the underside of fresh, gray, and black tanks to prevent freezing. Most modern cold-weather-package RVs come with these; older or warm-climate rigs may need them added.

Interior heat has to run constantly when temperatures drop. Propane furnaces work but burn through propane fast (a 30-pound tank can last two days in hard cold). Electric space heaters help reduce propane consumption but only work if you have shore power. Many full-time winterers use a combination.

Open cabinets under sinks. The interior heat doesn't reach inside closed cabinets where the plumbing lives. Cracking cabinet doors open lets warm air circulate around pipes.

Monitor temperatures. A wireless thermometer system that monitors interior, exterior, and underside (if accessible) lets you catch problems before they become damage. Several brands make these specifically for RV use.

For owners who want a full deep-dive on living in an RV through the winter, we'll have a dedicated guide on that soon. The summary version: it's doable, thousands of RVers do it every year, but the precautions are different from the storage-winterizing process this guide covers.

The Spring Recovery

When spring comes and temperatures stay reliably above freezing, you'll need to dewinterize before using the rig.

The short version of what dewinterizing involves: flush all the antifreeze out of the water system, disengage the water heater bypass, sanitize the fresh water tank, and check for any winter damage before pressurizing the system. We'll cover the full dewinterizing process in a separate guide.

Before that first spring trip, plan to do a thorough walk-around: check the roof for any cracked sealant or storm damage, inspect tires and inflate to road-ready PSI, test all systems before you actually leave the driveway. The goal is to catch any issues at home, not 200 miles into your first trip.

If you haven't done a full annual inspection recently, this is the moment for it. Our RV maintenance checklist covers what to check and when.

You've Got This

Winterizing sounds intimidating the first time you do it, but it's one of those RV tasks where the second time you do it, you wonder why it ever seemed hard. The principles are simple: get water out of places where it might freeze, protect what can't be drained, and don't forget the easy-to-miss components.

The hard part, as we said at the start, is knowing exactly what your specific rig needs. A motorhome winterizes differently from a fifth wheel. A 2019 Keystone has different specifics than a 2024 Grand Design. The owner's manual for your rig is the final authority on the details that matter for your specific setup.

RVKeeper builds a winterizing reminder into your maintenance plan automatically, based on your rig type and your storage location. The app knows which components your specific rig has and what each one needs. So you don't have to remember to start thinking about it. We'll remind you, and when you sit down to do the work, the steps will be there waiting.

Your rig will be ready next spring, and you won't be one of the rigs in the spring rush.