Winterize an RV: Beginner Guide for Your RV

Winterizing protects your RV during cold-weather storage. The process involves clearing water from the plumbing system — or replacing it with pink, non-toxic RV/marine propylene glycol — while stabilizing fuel and power systems and keeping interior moisture and pests in check. Done correctly, it prevents cracked fittings, pump damage, battery failure, and mold, and makes spring dewinterizing significantly faster.

Risks of skipping winterization (cracked fittings, pump damage, mold)

• Even one hard freeze can split PEX fittings, valves, and the water pump.
• Moisture left inside invites mold, mildew, and stubborn odors.
• Batteries can discharge or get damaged; untreated fuel can varnish or gum.

Two safe methods: antifreeze vs compressed air (and when to combine)

• Antifreeze method: After draining and bypassing the water heater, pump pink, non-toxic RV/marine propylene glycol through every fixture. Plan on roughly 2–4 gallons, depending on RV size and layout.
• Compressed air method: Use a regulator and city-water blow-out plug to clear lines. Set 30–40 PSI and never exceed about 50 PSI to protect fixtures.
• Hybrid approach: Blow out lines, then add antifreeze to P-traps and the water pump (often 1–2 gallons total).

Supplies and tools you’ll need

• Pink, non-toxic RV/marine propylene glycol (2–4 gallons full method; 1–2 gallons hybrid).
• City-water blow-out plug, air compressor with regulator (30–40 PSI; never exceed about 50 PSI).
• Water heater bypass kit (if not factory-installed), basic hand tools, towels, bucket.
• Desiccants or a safe, low-watt dehumidifier; breathable RV cover (avoid plastic tarps).

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Choose the method that fits your setup, then follow the correct steps for each.

Antifreeze method (full-system)

1. Close low-point drains and confirm the water heater is bypassed.
2. Use the RV’s winterize/siphon valve — or a hand pump — to draw antifreeze into the water pump.
3. Working one fixture at a time, open the hot side first, then cold, until pink flows at each: kitchen sink, bathroom sink, shower, and outdoor shower.
4. Flush the toilet until pink appears. For the city-water inlet, remove the screen and briefly depress the check valve with a non-marring tool to confirm coverage; wear eye protection.
5. Appliances (washer, ice maker): follow the owner’s manual for short winterization cycles.
6. Pour 1–2 cups of antifreeze into each drain and the toilet bowl to protect P-traps and seals.

Compressed air method (blow-out)

1. Once draining is complete, close the low-point drains.
2. Attach the blow-out plug at the city-water inlet and regulate pressure to 30–40 PSI — never exceed about 50 PSI.
3. Cycle through each fixture — hot first, then cold — until only air mist comes out.
4. Briefly open the low-point drains to purge any residual water, then close them again.
5. Add 1–2 cups of antifreeze to each drain and the toilet bowl, then introduce roughly 8–12 oz through the pump inlet or winterize pickup to protect the pump and check valves.

Once the main method is complete, finish with these final protection and safety checks before storage.

Protect traps and the water pump

• P-traps: Pour 1–2 cups per sink and shower drain to prevent freeze damage.
• Toilet: Add enough antifreeze to cover the valve seal.
• Pump: Add a small amount of antifreeze via the winterize pickup or inlet line to protect internal components.

Don’t forget fixtures: outdoor shower, toilet, washer/ice maker

• Outdoor shower: Run both hot and cold — pink for the antifreeze method, air-clear for blow-out.
• Appliances: Review manuals; many need brief dedicated cycles to purge water.
• City-water inlet: Confirm antifreeze (or air) reaches and clears the check valve.

Final checks and labeling for spring

• Leave valves in clearly labeled winter positions.
• Tag bypass and winterize settings so spring dewinterizing is straightforward.
• Do a final walk-through to confirm each fixture was run and every drain protected.

Warnings:

• Keep air pressure at 30–40 PSI and never exceed about 50 PSI to avoid damaging fixtures and check valves.
• Only use pink, non-toxic RV/marine propylene glycol in potable systems — never automotive antifreeze.
• Some tankless heaters must not be filled with standard RV antifreeze. Follow the heater manufacturer’s instructions.

A little preparation goes a long way here. Disconnecting parasitic draws, stabilizing fuel, and storing batteries and cylinders correctly can protect some of your most expensive components. For anything system-specific, check your owner’s manuals.

Lead-acid vs lithium battery storage and charging limits

• Lead-acid (flooded/AGM): Fully charge the battery, then disconnect the negative cable or connect a smart maintainer. Store it somewhere cool and dry, and check fluid levels in flooded cells before putting it away.
• Lithium (LiFePO4): Many lithium batteries cannot be charged below about 32°F. If you’re removing the battery for storage, aim for a 40–60% state of charge and follow your battery manufacturer’s recommendations.
• Shore power/solar: Use temperature-compensated charging for lead-acid. Set your solar charge controller to a storage profile to avoid overcharging.

For deeper battery guidance, see RV battery care and storage. Planning solar for storage season? See Solar on RVs: off-grid basics for storage season.

Propane cylinder and appliance safety for storage

• Close cylinder valves and confirm all appliances are off.
• If removing cylinders, store them upright in a well-ventilated area, following local codes.
• Run a quick leak check at all connections before storage — and again in spring.
• Cap propane quick-connects and appliance ports, and never store cylinders in living spaces or near ignition sources.

Generator, solar, and electronics

• Generator/engine: Add fuel stabilizer per the manufacturer’s instructions, run the engine to circulate treated fuel, and follow the storage steps in your manual.
• Solar: Confirm your charge controller’s storage settings to prevent overcharging.
• Electronics: Turn off inverters and nonessential breakers to reduce phantom loads.

The target is always before your area’s first hard freeze. In cold regions, that typically means mid to late fall. In milder climates, keep an eye on forecasts and be ready to act before cold snaps arrive.

If you’re still traveling through the season, blow out lines between trips, protect P-traps with antifreeze, and stay on top of moisture control.

If winter trips are on your list, see Winter RV rentals and tips.

Northern/Mountain regions: typical timing

Upper Midwest, Rockies, interior Northwest, and northern New England often winterize from late September to late October, depending on elevation and forecast.

Midwest/Northeast: first hard freeze planning

Expect October to early November in most areas. Winterize earlier if your storage spot is exposed or sits at higher elevation.

South/Coastal/High desert: what to do during occasional freezes

Full winterization may not always be necessary, but even a single hard freeze can cause damage. Blow out lines before cold snaps, protect traps with antifreeze, and consider heated storage during extended cold stretches.

DIY winterization comes down to supplies — RV antifreeze, a blow-out plug, and a regulator — plus 1–3 hours of your time. Shops offer bundled packages covering plumbing protection and basic system checks, with pricing that varies by region and RV class. Go DIY to save on labor, or use a shop when you want speed and a documented service record.

DIY cost and time ranges

• Supplies: 1–4 gallons RV/marine propylene glycol, blow-out plug, regulator (air method), desiccants, optional breathable cover.
• Time: Beginners often need 2–3 hours; experienced RVers can finish in around 60–90 minutes, depending on fixtures and appliances.

Shop service pricing and what’s included

• Typical inclusions: Drain and bypass water heater; antifreeze or blow-out service; trap and pump protection; quick fixture checks.
• Ask about appliance add-ons (ice maker, washer), battery care, and generator service. Pricing varies by RV type and region; confirm with local providers.

• Exceeding safe air pressure — stay at 30–40 PSI and never go above about 50 PSI.
• Skipping the water heater bypass before adding antifreeze.
• Missing lines: outdoor shower, city inlet, appliance feeds, or low-point drains.
• Using automotive antifreeze in potable systems — only pink, non-toxic RV/marine propylene glycol belongs here.
• Leaving batteries unattended for months without any maintenance.

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• Deep clean and fully dry sinks, shower, and counters; prop fridge and freezer doors open.
• Remove all food and scented items; place non-scented desiccants where they’re accessible.
• Seal potential entry points with copper mesh or steel wool where appropriate.
• Use a breathable, well-fitted RV cover and avoid plastic tarps. If storing outside, add tire covers and park on firm, well-drained ground.

When temperatures climb back up, reverse the process: return valves to their normal positions, flush out the antifreeze, sanitize the fresh water system, and test every fixture. Check batteries, propane, and appliances before your first trip out.