Complete Motorhome Winterization Checklist

Motorhome winterization: do it before first hard freeze. Photo: StowHelp.

1. When to Winterize (Regional Timing)

Winterize before the first hard freeze (overnight temps below 32°F/0°C). Water expands 9% when it freezes, and that expansion is what cracks PEX lines, water pumps, water heater tanks, and plumbing fittings. A single freeze night in an un-winterized motorhome can damage the entire water system.

Regional timing

• Upper Midwest, Northeast, Great Lakes: mid-October to early November. First hard freeze typically arrives late October; winterize early.
• Mid-Atlantic, Ohio Valley: late October to mid-November. Reliably cold by mid-November.
• Mountain West, high altitude: late September to mid-October. High elevation freezes earlier than the surrounding plains.
• Pacific Northwest: October to early November. Milder but still freezes occasionally inland.
• Southeast / Gulf Coast: often skip winterization entirely. Occasional hard freezes (every few years) do happen — monitor the 10-day forecast in winter and winterize if temps are predicted below 32°F.
• Desert Southwest: variable. Phoenix rarely freezes; Flagstaff freezes reliably. Check your specific local climate.
• Florida, South Texas: no winterization needed in most years. Keep fresh water in the system and use occasionally to prevent stagnation.

If in doubt, winterize. The cost of winterizing unnecessarily is ~$75 and 4 hours. The cost of not winterizing when needed is thousands in repairs.

2. Tools and Supplies You'll Need

Required

• 3-5 gallons of RV-specific antifreeze (pink, propylene glycol, non-toxic). Most RV stores carry it — Camco and Splash are the common brands. Cost: $4-$8/gallon.
• Air compressor capable of 40-50 PSI output. Small portable compressors work fine.
• Blow-out adapter — threads into your city water inlet, accepts an air chuck. $5-$15 at RV stores.
• Water heater bypass kit if your motorhome doesn't already have one installed. Most modern motorhomes have one built in; older units may not.
• Basic hand tools: screwdrivers, adjustable wrench, channel-lock pliers.
• Battery tender (see our long-term storage prep guide section 4 for recommendations).
• Fuel stabilizer (STA-BIL or equivalent).
• Engine oil + filter for the pre-storage oil change.
• Gloves, rags, drain pan.

Strongly recommended

• RV-specific wheel covers or tire boards
• Breathable RV cover (not a plastic tarp)
• Moisture absorbers (DampRid, silica gel packets)
• Rodent prevention supplies (steel wool, dryer sheets, peppermint oil)
• Roof vent covers (Maxx Air or similar)

3. Water System Winterization (The Critical Part)

This is where freeze damage happens. The water system includes fresh, gray, and black tanks, the water pump, water heater, water lines (hot and cold), every faucet, the toilet, shower, and any external hookups like outdoor showers or ice makers.

Step-by-step

Step 1: Drain fresh water tank

Open the low-point drain under the vehicle. Open all faucets (hot and cold) to help the water exit via air replacement. Wait 5-10 minutes for the tank to empty. Close the low-point drain.

Step 2: Drain the water heater

TURN OFF the water heater at the control panel AND at the LP gas / electric switch. Wait for it to cool (at least 30 minutes if hot). Open the pressure relief valve on the water heater. Remove the drain plug at the bottom of the water heater (on the exterior of the RV). Let it drain fully, which takes 10-15 minutes. Replace the drain plug hand-tight — don't over-torque or you'll strip the threads.

Step 3: Drain gray and black tanks

Dump at a dump station if possible, or at the facility's dump station. Flush the black tank thoroughly with the black tank flush system. Leave the valves closed after draining so residual fluids don't drip onto the facility floor.

Step 4: Blow out the water lines with compressed air

Thread the blow-out adapter into the city water inlet. Connect your air compressor. Set regulator to 40-50 PSI (higher can damage fittings). Open one faucet at a time — starting with the furthest (kitchen sink cold, then hot, then bathroom sink, then shower, then toilet, then any outdoor connections). Let each run until only air comes out. Don't forget the toilet sprayer, outdoor shower, ice maker line, and washing machine line if equipped.

Step 5: Bypass the water heater

The water heater bypass valves divert antifreeze AROUND the water heater so you don't waste 6-10 gallons filling the heater tank. If equipped, turn the bypass valves to bypass position. If not equipped, you'll need to install a bypass kit (about $20 at any RV store) or accept that you'll use extra antifreeze.

Step 6: Add antifreeze to the system

Two common methods:

1. Pump method: Disconnect the water pump intake from the fresh water tank and connect it to a jug of antifreeze. Turn on the pump. Open faucets one at a time (kitchen cold, then hot, then every other faucet including shower, toilet, outdoor) and run each until pink antifreeze comes out. Total antifreeze: 3-5 gallons depending on system size.
2. City water method: Use a winterizing kit that connects antifreeze to the city water inlet. Works but may not reach all fittings.

Step 7: Add antifreeze to every P-trap

Pour a cup of antifreeze down every sink drain, shower drain, and toilet. This protects the P-traps (the U-shaped pipes below drains that hold water to prevent sewer gas from rising). Even tiny amounts of water in P-traps freeze and crack the fitting.

Step 8: Add antifreeze to the black tank

Pour a half-gallon of antifreeze into the toilet and flush — this protects the black tank's internal valves and sensors from residual water.

Step 9: Cap external water connections

Put caps on the city water inlet and any other external water connections to prevent dirt, insects, and moisture intrusion.

Water system is done. Pink antifreeze should be visible at every faucet. The system is now freeze-proof down to about -50°F.

4. Engine and Chassis Preparation

For motorized RVs (Class A, B, C), the chassis engine needs the same treatment as any stored vehicle. Travel trailers skip this section since they don't have their own engine.

Fuel system

Fill the fuel tank to 90-95%. Add fuel stabilizer (STA-BIL, Sea Foam, Star Tron). Drive 10-15 miles so the stabilized fuel circulates through injectors and fuel lines. This is the same protocol as our passenger vehicle storage guide.

Oil change

Change oil AND filter before storage. Used oil is acidic; fresh oil isn't. Run the engine 10 minutes after the change so fresh oil coats internal components.

Coolant

Check coolant level and concentration. 50/50 antifreeze/water ratio is standard. In high-elevation or extreme-cold storage (below -20°F), move to 60/40.

Other fluids

Top off transmission fluid, power steering, brake fluid, windshield washer fluid (empty in cold climates to prevent reservoir cracking).

Chassis battery

Install a battery tender on the chassis battery (the one that starts the engine). See tender brand recommendations in our main storage prep guide section 4.

5. Batteries and Electrical Systems

Motorhomes have two battery systems: the chassis battery (engine starting) and the house batteries (lights, appliances, accessories). Both need attention.

House batteries

• Ideally disconnect house batteries entirely — remove the negative terminal or use the battery cutoff switch if equipped. This eliminates parasitic loads (clocks, alarms, memory) that would otherwise drain the batteries.
• Alternative: connect a tender to the house batteries if your storage location has 110V access. Keeps the batteries fully charged throughout storage.
• For lithium house batteries (LiFePO4 — increasingly common in new RVs), follow the manufacturer's specific storage guidance. Most lithium batteries should be stored at 50-70% state of charge, not 100%, for long-term preservation.

Chassis battery

Same as any vehicle — disconnect or put on a tender. Don't forget this one. Many RV owners focus on house batteries and forget the chassis, then return in spring to a dead truck that won't start.

Solar systems

If your RV has solar panels and a charge controller, the solar itself will trickle-charge the batteries during storage if they're connected. No special action needed for the panels. Verify the charge controller has a "storage" or low-voltage mode that prevents overcharging.

Inverters and converters

Turn off the inverter at the main switch to prevent phantom loads. The converter (which charges batteries from 110V shore power) can stay on if you're leaving batteries connected to tenders.

6. Propane, Appliances, and Interior

Propane system

• Close the main valve on each propane cylinder.
• Close individual appliance valves inside the cabin (stove, furnace, water heater).
• Some states require LP tanks to be removed entirely for covered or indoor storage — check with the facility.

The National Fire Protection Association NFPA 1192 standard (RV fire safety) requires propane valve closure before transport or storage. Facilities that store RVs at scale enforce this.

Refrigerator

Empty the refrigerator and freezer. Clean all surfaces. Prop the doors open (use a wedge or the "storage mode" latch if equipped). An open door prevents mold and mildew. For absorption (LP-powered) refrigerators, turn off at the control panel.

Stove and oven

Clean thoroughly — food residue attracts rodents. Turn off LP at the appliance valve.

Furnace

Turn off at the thermostat AND at the LP supply valve. Change or remove filter. Inspect the exhaust vent for blockage.

Interior cleaning

• Empty all cabinets and drawers of food, trash, and anything with a smell.
• Vacuum all carpets and upholstery.
• Wipe leather with conditioner.
• Place moisture absorbers (DampRid, silica gel) in cabinets, drawers, and refrigerator.
• Dryer sheets in drawers and closets deter both moisture and rodents.
• Leave cabinet doors slightly ajar to promote air circulation.

7. Tires, Awnings, Roof, Slide-Outs

Tires

• Inflate to maximum sidewall pressure (not door-jamb pressure — we want to MINIMIZE flat-spotting).
• Use tire covers to block UV, especially in southern climates.
• Consider tire cradles or boards under each tire for storage longer than 6 months.
• Check tire age — DOT code on the sidewall. Tires older than 6 years should be replaced regardless of tread.

For trailer-specific tire considerations see trailer storage guide.

Awnings

Fully retract and secure all awnings. Partial extension + wind = torn awning. This is one of the most expensive "small" RV damages ($800-$2,500 to replace a large main awning).

Slide-outs

Retract fully. Lubricate slide rails with silicone spray before retracting. Wipe slide seals clean and condition with a dedicated RV slide-seal conditioner (Thetford or 3-in-1 products). Dry slide seals crack over winter and leak water in spring.

Roof

Inspect for sealant failures, caulking gaps, damaged vents. Repair BEFORE winter — sealant cures poorly below 40°F. Key areas: vents, skylights, antenna bases, A/C shroud edges, where walls meet roof.

Cover roof vents with vent covers that allow airflow but block rain and snow.

Exterior

• Wash the exterior thoroughly.
• Apply wax to painted surfaces and fiberglass.
• Condition rubber seals around doors, windows, and storage compartments.
• Check and clean storage compartment locks.

8. Rodent and Pest Prevention

Motorhomes are disproportionately affected by rodent damage because they're essentially small houses with food-prep areas, comfortable nesting spots, and lots of entry points. The CDC documents rodent-borne diseases (hantavirus, leptospirosis) that make rodent cleanup a health hazard, not just a repair hazard.

Essential steps

• Park on concrete, asphalt, or gravel — never grass.
• Seal all exterior openings: cover vents, seal propane supply entry points with steel wool, cover exhaust pipe, check for any gaps around plumbing penetrations.
• Inspect weather stripping around doors and compartments — replace any damaged seals.
• Deploy peppermint oil on cotton balls throughout the interior and in storage compartments.
• Place dryer sheets in drawers, under beds, in storage compartments.
• Ensure all food is removed from the interior.
• Consider electronic deterrents (mixed evidence but cheap).

What NOT to do

• Don't use poison inside the RV. A rodent that dies in a wall cavity or HVAC duct is a much worse problem than the live rodent.
• Don't rely on one deterrent — layer them.
• Don't leave any food or soaps/toiletries with scents that attract rodents.

Full rodent-prevention details in our main storage prep guide section 7.

9. Class-Specific Notes

Class A motorhomes

Largest size class, most complex systems. Additional considerations:

• Hydraulic leveling jacks — retract fully before storage, lubricate cylinders, and protect exposed rams with plastic bags or purpose-made covers.
• Generator — run for 30 minutes under load before storage (to prevent carburetor gumming), then shut down, treat with fuel stabilizer.
• Air brakes (on larger diesel pushers) — release parking brake, chock wheels instead.
• Hydraulic suspension / air bags — follow manufacturer storage guidance, typically lower to contact stops.

Class A storage space requirements are substantial — find RV storage facilities with large-vehicle capacity.

Class B camper vans

Smaller, simpler. Key considerations:

• Most Class Bs are converted passenger vans — the chassis storage protocol is identical to a standard van.
• Some Class Bs have no water system (or a minimal one) — simpler winterization.
• Roof popups require specific retraction and sealing.
• Solar panels often integrated; follow section 5 solar guidance.

Class C motorhomes (cab-chassis RVs)

Mid-size, mid-complexity. Considerations:

• Over-cab sleeping area — inspect for leaks before storage, reseal if needed.
• Exterior storage compartments typically larger than Class A — ensure all empty and sealed.
• Cab A/C (separate from house A/C) needs its own winterization check.

Travel trailers (towable)

No engine, simpler winterization:

• Water system winterization is identical to motorized RVs.
• Battery system similar but typically smaller (often just one or two house batteries).
• Tires and awnings same as motorized RVs.
• Hitch — grease the ball and coupler. If stored on a trailer ball, use a ball cover; if dropped on jack stands, check stand condition and ground contact.

Fifth wheels

Similar to travel trailers with additional considerations:

• Kingpin greased and covered.
• Landing gear lowered to full extension and rested on boards or pads (not bare ground).
• Often have slide-outs on multiple sides — careful slide retraction and seal conditioning.

10. Spring De-Winterization (Reactivation)

Reversing winterization is simpler but equally important. Work through in order.

Water system reactivation

1. Turn water heater bypass valves back to normal position.
2. Close all faucets.
3. Reconnect fresh water tank intake to the water pump (if disconnected for winterization).
4. Fill fresh water tank partially (5-10 gallons).
5. Turn on water pump. Open each faucet one at a time — let pink antifreeze run out until clear water runs. Do cold first, then hot.
6. Flush toilet multiple times until clear water runs.
7. Fill fresh water tank completely, then drain completely — this helps flush residual antifreeze.
8. Repeat until antifreeze taste is gone from water (typically 2-3 tank fills).
9. Replace water filter if equipped.
10. Sanitize the fresh water system with a diluted bleach solution (1/4 cup bleach per 15 gallons of water — let sit 15 minutes, then flush twice with clean water). The EPA recommends this protocol for potable water systems after extended non-use.

Engine reactivation (motorized RVs)

Follow the return-from-storage checklist in our long-term storage prep guide section 9. Remove any tailpipe/intake plugs. Re-inflate tires to normal pressure. Check all fluids. Start engine and let reach operating temperature before driving.

Battery reactivation

Reconnect batteries, disconnect tenders. Test voltage on all batteries; any reading below ~12.4V (lead-acid) or the manufacturer-spec low for lithium means the battery may be at end of life.

Propane reactivation

Open main propane valves. Check for leaks using soapy water at each fitting (bubbles = leak). Test each appliance one at a time. Some regions have mandatory annual LP inspections before use.

Refrigerator reactivation

Close doors. Turn on. For absorption refrigerators, allow 12-24 hours to reach operating temperature. For compressor refrigerators, 4-8 hours.

Slide-outs

Clean slide tops of any debris accumulated over winter. Extend slowly. Inspect seals and rails.

Final inspection before travel

Walk the vehicle inside and out. Look for signs of rodent activity (droppings, chewed material). Check under beds, in cabinets, in storage compartments, and under the hood. If you find evidence of rodents, wear an N95 mask during cleanup per CDC guidance.

FAQ

When should I winterize?

Before first hard freeze in your region. Mid-October to early November in the Northeast / Midwest; late November in Mid-Atlantic; December or skip in the Southeast.

Drain water or use antifreeze?

Both. Drain first, then blow out lines with compressed air, then add RV antifreeze to every P-trap and water line. Draining alone leaves water in low spots.

What's the difference between RV antifreeze and automotive?

RV antifreeze is non-toxic propylene glycol (pink, safe in water systems). Automotive antifreeze is toxic ethylene glycol (green/orange, for engine cooling only). Never use automotive in water systems.

Can I winterize myself?

Yes. 3-5 hours of work, $50-$100 in supplies. Professional winterization by a dealer runs $300-$700.

How long does winterization last?

Indefinitely in terms of freeze protection. Water antifreeze doesn't lose effectiveness sitting. Most owners leave everything winterized for the entire storage period (3-6 months).

Can I still use the RV during winter if it's winterized?

No. The water system is inactive. You can sleep in it (bring bottled water) but you can't use faucets, toilet, or shower. For actual winter camping you need a 4-season RV and active heating systems.

What if I only store the RV for 2-3 months?

Still winterize if any freezing temperatures are expected during the storage period. One freeze night is all it takes.

What about solar panels?

No special winterization needed for panels themselves. Verify charge controller is set to storage/low-voltage mode if leaving batteries connected.

Do I need to remove the batteries?

Not necessarily — a tender works. If no shore power available at storage, disconnect to prevent parasitic drain.

Can the facility winterize for me?

Some RV-focused facilities offer this as a paid service ($200-$500). Check with your facility. For self-storage facilities that aren't RV-specific, expect no winterization service.

Next Steps

Work the checklist in order when you're 1-2 weeks out from planned storage. Set aside a weekend day for Class A motorhomes, a Saturday morning for travel trailers.

Related guides:

• 47-Point Long-Term Storage Prep Checklist (all vehicles)
• When Should You Book Winter RV Storage?
• RV Storage Tips
• Snowbird Vehicle Storage Logistics

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