How to Winterize Your RV: Step-by-Step

Skip winterization and you’re looking at cracked pipes, a blown water pump, and a repair bill that’ll hit $2,000–$5,000 before you even get a quote on the slide-out seals. I’ve watched it happen to experienced campers who figured one mild winter wouldn’t matter. It always matters.

Done right, winterization takes three to four hours the first time, under two once you’ve run through it a season or two. What follows is the same process I use on my 2019 Grand Design Reflection 297RSTS — and have walked a dozen clients through on everything from Class A motorhomes to teardrop trailers.

What You’ll Need Before You Start

Don’t start draining lines and then realize you’re short on antifreeze. Pull everything together first. Core supplies: non-toxic RV antifreeze (pink stuff, not automotive), a water pump converter kit or bypass kit, a hand pump or compressor with a blow-out adapter, and basic hand tools.

For antifreeze, I use Camco’s RV antifreeze — non-toxic, rated to -50°F burst protection, runs about $5–$6 per gallon. Most rigs need 2–3 gallons. Buy four. The Camco RV Winterization Kit bundles the antifreeze pump, blow-out adapter, and bypass fittings in one box — worth it if this is your first time through the process.

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You’ll also want Teflon tape, a wet/dry shop vac, and a torque wrench if you’re pulling the anode rod. If you’re blowing out lines with compressed air — which I do every time, not just as an option — use a regulator capped at 50 PSI. Above that, you risk joint damage on older fittings.

Step 1: Drain and Flush the Fresh Water System

Dump your fresh water tank completely. Open every faucet — hot and cold — inside the rig, including the outdoor shower if you have one. Flush the toilet until it runs dry. This clears the bulk of standing water before you introduce antifreeze or air.

Find your low-point drain valves. Most RVs have two — one hot, one cold — tucked under the rig near the water heater. Open both and give them five to ten minutes to drain. On my Grand Design, there’s a third low-point drain near the wet bay that most people walk right past. Check your owner’s manual for your specific layout before you assume you’ve got them all.

Once drained, close the low-point valves. You’re not done with the water system — this is just the first pass.

Step 2: Bypass and Drain the Water Heater

Don’t pump antifreeze through your water heater. A standard 6-gallon tank will eat your entire antifreeze supply before you touch the actual lines. Install a water heater bypass kit if your rig doesn’t already have one — most rigs built after 2015 do.

With the bypass engaged, the water heater is isolated from the rest of the plumbing circuit. Let it cool completely before you drain it — minimum two hours after last use. Remove the pressure relief valve and the drain plug (usually a 1-1/16″ plug on the lower side of the tank). Let it drain fully, reinstall the plug with fresh Teflon tape. Hand-tight plus a quarter turn. Don’t crank it.

If your water heater has an anode rod — Atwood and Dometic units typically do — pull it now and look at it. More than 50% depleted, replace it before spring. A fresh anode rod is $8 and it’s the only thing standing between your tank lining and corrosion.

Step 3: Blow Out the Lines with Compressed Air

This is the step that separates a solid winterization from one that fails in February. Antifreeze alone won’t displace water sitting in low spots and P-traps. Blow the lines first, then run antifreeze — that’s the sequence, every time.

Connect a blow-out adapter to your city water inlet. Set your compressor regulator to 40–50 PSI. Starting at the farthest fixture from the inlet, open each faucet one at a time — hot side first, then cold. Hold each open until you get nothing but air. Work back toward the inlet systematically: rear bathroom, kitchen, front bathroom if you have one.

Don’t skip the toilet. Hold the flush pedal down and let it blow clear. Same with the outdoor shower and any icemaker lines on a residential fridge. Those icemaker lines hold water in a tight coil and crack clean through in a hard freeze.

Step 4: Pump Antifreeze Through the System

Lines blown clear, now you run antifreeze. Connect your pump converter kit to the fresh water pump so it draws directly from a jug instead of the fresh tank. If your rig has a dedicated antifreeze inlet on the bypass kit, use that.

Turn the pump on and work through every fixture the same way you did with the air — farthest first, hot then cold. You’re looking for pink fluid at each tap. Once you see it, close that faucet and move to the next. Pour a cup of antifreeze directly into each drain — sinks, shower, tub — to protect the P-traps. Two cups into the toilet bowl, flush it through.

Check the toilet’s water valve. There’s usually a small hand spray or foot pedal valve that holds water. Make sure antifreeze gets through it before you move on.

When you’re done, shut off the pump and crack a faucet to release pressure. Leave the system depressurized for storage.

Step 5: Winterize the Propane System

Propane doesn’t freeze, but the system still needs attention before you park the rig. Close the main propane valve at the tank. Run each appliance — furnace, range, water heater — until the lines purge and the flames die out. That clears residual gas from the supply lines.

Inspect all exterior propane connections and regulator covers for cracks, corrosion, or pest intrusion. Wasps nest in regulator vents over summer; a blocked vent causes pressure problems the first time you fire it up in spring. Cover the regulator with a propane regulator cover rated for UV and moisture. Ten dollars. It extends regulator life by years.

Disconnect tanks if your storage facility requires it, or leave them connected but closed if you’re storing on your property. Either way, tanks stay upright and never in an enclosed space. If your cylinders are approaching the 20-year DOT recertification mark, handle that before spring.

Step 6: Battery Maintenance and Storage

A neglected battery bank is the second most common source of spring headaches, right behind frozen pipes. Lithium (LiFePO4) handles cold better than lead-acid, but neither chemistry likes sitting at partial charge for months.

For lead-acid and AGM: fully charge before storage, then connect a smart maintainer for float charging. I’ve run the NOCO GENIUS10 on my rig for three winters straight. It handles 6V and 12V banks, has a repair mode for sulfated batteries, and won’t overcharge. Set it and leave it.

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No shore power at your storage location? Disconnect the batteries entirely and store them somewhere above 32°F — a garage or basement works. A fully charged AGM holds for 3–6 months without a maintainer. A discharged one sulfates and dies. Check voltage monthly if you’re going without a maintainer.

For lithium, store at 50–80% charge per your manufacturer’s spec. Most modern BMS systems handle cold storage without issue, but check your battery brand’s documentation — some recommend disconnecting below -4°F.

Step 7: Exterior and Roof Prep

Water infiltration through a failed seal does more cumulative damage than a frozen pipe. Spend an hour on the roof before you park it — it’s the highest-return hour in the whole process.

Walk the entire roof and inspect every seam, vent, skylight, and antenna mount. On EPDM rubber roofs, look for cracks, bubbling, or separation at the edges. On fiberglass, check for crazing around hardware. Use Dicor self-leveling lap sealant on any gaps — it flows into cracks and cures to a flexible, weather-tight seal. Don’t use silicone. It doesn’t bond to EPDM and it’ll peel off before April.

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Wipe down all slide-out seals with a rubber conditioner. Dry, cracked slide seals run $300–$800 to replace. A $12 bottle of conditioner prevents that. Lubricate all slide mechanisms per your manufacturer’s spec — most call for dry PTFE lubricant, not grease.

Check the underbelly if your rig has an enclosed one. Any gap a rodent can fit through, pack with steel wool before you add foam. Rodents chew through foam without slowing down; they won’t touch steel wool. Cover all exterior vents — refrigerator, furnace exhaust, water heater — with mesh vent covers to block nesting.

Storing outdoors? A breathable RV cover is worth it on a rig you care about. Non-breathable covers trap moisture and cause more damage than no cover at all. Strap it down with wind-rated straps — a cover that blows off in a January storm and drags across the roof is a problem you created.

Step 8: Interior Prep

Pull all food out of the rig — every can, every crumb, every granola bar that fell behind the seat cushion. Rodents will find it before you do. Leave cabinet doors open so air circulates and moisture doesn’t build up in corners. Put DampRid or similar moisture absorbers in the bathroom, kitchen, and bedroom.

Residential fridge? Prop the doors open with a folded towel to prevent mold. RV-style absorption fridges get turned off, emptied, and left open the same way. Wipe down all interior surfaces before you close up — coming back to a clean rig in April is worth fifteen minutes of work now.

Pull the window shades to block UV on interior fabrics and surfaces. Close all roof vents, but if you’re in a humid climate, leave one cracked slightly for minimal airflow — just enough to prevent moisture buildup without letting in precipitation.

What This Costs If You Skip It

A full DIY winterization runs $40–$80 in supplies and an afternoon of your time. A single cracked water line in a wall cavity — the kind that soaks insulation and subfloor before you find it in April — runs $1,500 to $4,000 to repair properly. I’ve seen a burst pipe near a slide-out mechanism turn into a $6,000 job when the water reached the electrical harness.

Do it right once, build the muscle memory, and it’s a two-hour routine at the end of every season.

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