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:
- 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.
- 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.
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
How do you winterize a Class A motorhome?
Run the full water-system steps in section 3 first; a Class A has the same plumbing as any other RV, just longer runs and often a washer line to drain and antifreeze and an ice maker line to drain and blow dry (see the ice maker steps). Then handle the systems only the largest size class has:
- 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.
How do you winterize a Class B camper van?
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.
How do you winterize a Class C motorhome?
A Class C is winterized like a Class A on the house side: drain, blow out and antifreeze the water system per section 3, then prepare the engine like any stored van or truck per section 4. The cab-chassis layout adds a few checks:
- 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.
How do you winterize a travel trailer?
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.
How do you winterize a fifth wheel?
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.
How do you winterize an RV ice maker?
Drain it and blow it dry instead of filling it with antifreeze. Dometic's winterizing instructions for its RM1350 ice maker refrigerators explain that the heat tape wrapped around the water solenoid valve only runs while the refrigerator has 12V DC power, so if the RV is stored with the refrigerator or DC power off and the temperature can fall below 32 F, the ice maker and any water dispenser must be drained to prevent component damage and leaks (Dometic RM1350 winterizing instructions).
- Level the RV, shut off the ice maker's water supply valve and set a shallow pan under the water solenoid valve.
- Remove the inlet fitting at the valve and drain the supply line, then disconnect the outlet line to the ice maker and drain it.
- Connect compressed air to the valve inlet and run a harvest cycle so the air clears the water trapped in the valve.
- Empty the ice bin and leave it dry.
Dometic says this procedure should be done by qualified service personnel because it needs water, compressed air and AC power. Norcold and residential refrigerators use different fittings and steps, so follow the manual for your model, and if a dealer or storage facility winterizes the coach, ask them to confirm the ice maker line was drained.
How do you prepare a diesel motorhome's fuel for winter storage?
The fuel itself gets the same treatment as any stored vehicle in section 4: fill the tank to 90 to 95 percent to limit condensation, add a stabilizer made for diesel, and drive long enough to pull treated fuel through the filters and injectors. What is different on most newer diesel pushers is diesel exhaust fluid (DEF) for the SCR exhaust system.
- DEF freezes at about 12 F, and SCR-equipped trucks have component heaters for cold weather, so no extra step is needed just because it might freeze (Navistar DEF tips, NHTSA).
- Never add water, antifreeze or any other additive to the DEF tank; only approved DEF meeting ISO 22241 belongs in it.
- DEF expands as it freezes and can damage a tank that is full or nearly full, and heat shortens its life: the American Petroleum Institute says DEF stored at 86 F or higher lasts about six months, while properly stored DEF can last 12 months or longer (API DEF guidance).
Check your chassis owner's manual for the DEF level it recommends before long storage, and plan to top off with fresh DEF in spring if the coach sat through a hot summer.
10. Spring De-Winterization (Reactivation)
Reversing winterization is simpler but equally important. Work through in order.
Water system reactivation
- Turn water heater bypass valves back to normal position.
- Close all faucets.
- Reconnect fresh water tank intake to the water pump (if disconnected for winterization).
- Fill fresh water tank partially (5-10 gallons).
- 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.
- Flush toilet multiple times until clear water runs.
- Fill fresh water tank completely, then drain completely - this helps flush residual antifreeze.
- Repeat until antifreeze taste is gone from water (typically 2-3 tank fills).
- Replace water filter if equipped.
- 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.
Do you take the wheel chocks off an RV for winterization?
No. Leave the wheels chocked for the whole time the RV is stored. Chocks are what keep a parked coach from rolling, and this checklist recommends releasing the parking brake on diesel pushers with air brakes and relying on chocks instead. Chock both sides of a tire on level ground, check them whenever you visit, and pull them only when you are ready to drive in spring.
How do you winterize a Class A motorhome?
Drain every tank and the water heater, blow out the lines with compressed air, and pump RV antifreeze through each faucet, shower and P-trap, including any washer line; drain and blow out the ice maker line instead of filling it with antifreeze. Then add the Class A steps: retract and protect the leveling jacks, run the generator under load before treating its fuel, release air brakes and chock the wheels, and follow the maker's guidance for air-bag suspension.
How do you winterize an RV ice maker?
Drain it and blow it dry rather than filling it with antifreeze. Dometic's instructions for its RM1350 ice maker refrigerators say the heat tape on the water valve only works while the fridge has 12V power, so if the RV is stored with the fridge or DC power off and temperatures can fall below 32 F, the ice maker and any water dispenser must be drained to prevent damage and leaks. Shut off its water supply, drain the line at the water valve, then clear it with compressed air. Follow the manual for your model.
How do you prepare a diesel motorhome's fuel for winter storage?
Fill the tank to 90 to 95 percent, add a stabilizer made for diesel and drive long enough to pull treated fuel through the filters and injectors. Treat the diesel exhaust fluid (DEF) differently: it freezes at about 12 F, the truck's DEF heaters thaw it, and you should never add water, antifreeze or any additive to the DEF tank. DEF expands as it freezes and can damage a tank that is full or nearly full, and heat shortens its life, so check the chassis manual before storing.
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.
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