Winter demands respect from RV owners. When water freezes, it expands by roughly 9% — enough to crack fittings, split valve bodies and destroy water pumps. A few hours of fall maintenance can save thousands in spring repair bills and protect your manufacturer's warranty. Neglect it, and you may discover burst pipes and cracked fittings when you should be enjoying your first camping trip of the year.

This guide walks through every step: choosing your winterization method, selecting the right antifreeze, detailed procedures for different RV types, battery storage, tire care, exterior protection and spring de-winterization.

Understanding What Freezes and Why

Modern RVs typically use PEX tubing, which has some flex to absorb ice expansion. But PEX isn't freeze-proof. Repeated freeze-thaw cycles fatigue the material, and the fittings, crimp rings and connected components remain the most vulnerable points.

The components that fail first and most often:

• Toilet valve assemblies: The intricate plastic housing of the water module cracks when residual water freezes inside. This is the single most common freeze-related failure.
• Water pumps: Diaphragm pumps contain check valves and flexible diaphragms made of materials like Santoprene or EPDM. These become brittle and crack in freezing conditions.
• Rigid fittings and brass valves: Zero tolerance for expansion. Ice pressure cracks them before anything else gives.
• Filtration housings: Plastic filter bodies crack and leak after a single hard freeze.

Understanding where the weak points are in your system tells you where to focus your winterization effort.

Choosing Your Method: Air vs. Antifreeze

Two approaches dominate RV winterization. Both aim to displace water from the plumbing, but they work differently and have different reliability profiles.

Compressed air method: Uses an air compressor to blow water from the lines. No chemicals enter your potable water system, which simplifies spring de-winterization. The downside: it's nearly impossible to remove all water using air alone. Pockets collect in low spots, valves and pump chambers. This method works best as a supplement to antifreeze, not a replacement.

Antifreeze method: Pumps RV-specific antifreeze through the entire plumbing system, displacing water and providing freeze protection down to -50°F or lower. More reliable for complete coverage. The trade-off is that you'll need to flush the system thoroughly in spring.

For most RV owners, the antifreeze method is the right choice. It provides better protection with less risk of missed spots. If you prefer compressed air, use it in combination with antifreeze in the P-traps and pump.

Choosing the Right Antifreeze

This is the single most important decision in the winterization process, and the one most prone to dangerous mistakes.

Never use automotive antifreeze (ethylene glycol) in your RV. Ethylene glycol is highly toxic. Even small amounts can cause kidney failure in humans and pets. It's designed for engine cooling systems, not drinking water plumbing. There are no exceptions to this rule.

RV-specific antifreeze uses propylene glycol or ethanol blends and is non-toxic for incidental contact with potable water systems. Here's how the options compare:

Ethanol/alcohol blend ($3-$5/gallon): The budget option. Offers freeze protection but actively dries out rubber seals in faucets, toilet valves and pump diaphragms. Spring leaks are a common consequence. Also flammable and leaves an unpleasant taste. Not recommended despite the lower price tag.

Pure propylene glycol ($6-$12/gallon): The premium choice. Lubricates seals rather than drying them out, is non-toxic, leaves no aftertaste and provides protection down to -50°F to -100°F depending on concentration. The higher upfront cost is repaid by avoiding seal-related repairs in spring. This is what RV manufacturers recommend.

Bio-based (glycerin/vegetable oil, moderate cost): More environmentally friendly, good seal compatibility, adequate freeze protection. Can be more viscous and slightly harder to pump. A reasonable middle ground.

Important distinction: The temperature rating on the bottle (e.g., -50°F) refers to the burst point — the temperature at which pipe damage occurs. The antifreeze may turn slushy around +20°F, but that slush doesn't expand enough to cause damage. This is normal and expected.

How much you'll need: Travel trailers typically require 2-3 gallons. Larger fifth wheels or Class A motorhomes with washing machines, ice makers and outdoor kitchens may need 4-6 gallons. Always have extra on hand.

Step-by-Step Winterization Procedures

General Preparation (All RV Types)

Before any model-specific steps, complete these universals:

1. Drain all holding tanks at an approved dump station. Fresh water, gray water and black water. Flush the black tank thoroughly with a rinse wand or built-in rinse system to prevent waste buildup and odors during storage.

2. Turn off the water heater (both gas and electric switches) and let the water cool completely before draining. Locate and remove the drain plug. Open the pressure relief valve to allow complete drainage. Inspect the anode rod for corrosion and replace if needed. This is a good time to do it.

3. Remove inline water filters. Antifreeze damages charcoal filter elements. Install a bypass hose to maintain system continuity if your plumbing requires one.

Travel Trailers (Jayco Jay Flight, Open Range Models)

1. Bypass the water heater. Locate the bypass valves behind the heater. On a 3-valve system: close the cold water inlet valve and the hot water outlet valve, then open the bypass valve connecting the cold and hot lines. On a 2-valve system: turn both valves to the bypass position. Refer to your owner's manual for exact valve orientation. It varies by model.

2. Connect the antifreeze supply. Find your water pump (typically under a bunk, dinette seat or kitchen sink). Disconnect the inlet hose from the fresh water tank side. Attach a siphon hose to the pump inlet and place the other end in a jug of propylene glycol antifreeze.

3. Run the pump and distribute. Turn on the water pump. Open the faucet furthest from the pump (both hot and cold) until you see a steady stream of pink antifreeze. Work your way backward through each faucet in sequence. Flush the toilet until pink fluid appears in the bowl. Briefly open the low-point drains (under the RV) until antifreeze flows, then close them.

4. Protect the P-traps. Pour about one cup of antifreeze into each sink drain and the shower drain. This prevents the water in the trap from freezing and cracking the fitting.

Fifth Wheels With Centralized Utility Centers (Jayco Eagle/Pinnacle, Heartland RV Bighorn)

Many modern fifth wheels use a centralized docking station (like the Jayco Uni-Dock) with color-coded valves that simplify winterization.

1. Configure the utility center. Set valves to "Winterize" or "Sanitize/Winterize" mode. This automatically bypasses the water heater and aligns the pump to draw from the city water inlet rather than the fresh tank.

2. Connect the supply. Attach a short garden hose from the city water inlet to a jug of antifreeze.

3. Pump and distribute. Turn on the water pump and open all faucets and fixtures. Including outdoor shower and outdoor kitchen. Until pink antifreeze flows steadily from each one.

4. Tankless water heaters: If your fifth wheel has a Truma AquaGo, open the yellow "Easy Drain Lever" to drain the mixing vessel. Do not pump antifreeze through the Truma unless you have a specific bypass kit. Draining is sufficient for most conditions.

Class A and Class C Motorhomes (Entegra Coach, Jayco Seneca)

Motorhomes often feature residential appliances that need separate winterization attention:

Washing machine (Splendide): Pour antifreeze into the drum and run a "Spin" cycle to force it into the drain pump and P-trap. Then select a "Warm" wash cycle to open both hot and cold valves. Let the machine fill until pink antifreeze enters the drum, then cancel the cycle and drain.

Residential refrigerator with ice maker: Cycle the ice maker until pink-colored ice appears (discard all antifreeze ice). Depress the water dispenser paddle until pink antifreeze flows through.

Macerator toilets: Flush until antifreeze passes through the macerator pump, protecting the internal blades and housing.

Compressed Air Alternative

Connect a blow-out plug to the city water inlet. Set the compressor to 30-40 PSI maximum. Exceeding 40 PSI risks damaging plumbing lines. Open each faucet (hot and cold) one at a time while applying air pressure until no water is expelled.

Remember: this method does not fully protect the water pump (bypassed by the city water inlet) or the P-traps. You still need to run the pump briefly to clear it and pour antifreeze into every drain.

Battery Maintenance During Storage

Battery neglect is the leading cause of premature battery failure in RVs. Different chemistries have different vulnerabilities.

Lead-acid (flooded): A fully charged battery has a freeze point of -92°F. At 40% charge, it freezes at just +16°F. Well within normal winter temperatures. Self-discharge rate: 5-15% per month. During storage, check water levels monthly and add distilled water as needed to keep plates submerged.

AGM (Absorbed Glass Mat): Sealed, maintenance-free, more freeze-resistant than flooded lead-acid. Self-discharge: 1-3% per month. Still needs periodic maintenance charging.

Lithium (LiFePO4): Cannot be charged below 32°F without risking permanent damage unless the battery has an internal heater (verify with your manufacturer). Very low self-discharge at 2-3% per month. Store at 50-60% state of charge. Do not continuously trickle charge unless the Battery Management System specifically supports a storage mode.

Storage Procedure (All Types)

1. Fully charge batteries to 100% before storage. This is the single most effective step against sulfation and freeze damage.
2. Physically disconnect the negative cable from the battery terminal. Battery disconnect switches don't always catch every parasitic circuit.
3. In harsh-winter climates, consider removing batteries and storing them indoors above freezing.
4. Use a smart trickle charger (battery maintainer) for lead-acid and AGM. These adjust charging current automatically and prevent overcharging. For lithium batteries, check voltage every 2-3 months.

Solar Panels During Storage

If storing outdoors with solar panels, verify your charge controller is compatible with your battery type and that temperature compensation is enabled. If your RV is under a cover that blocks sunlight, disconnect the panels from the controller to prevent potential nighttime drain from low-quality controllers.

Tire Care During Storage

RV tires face two primary threats during long-term storage: flat spotting and UV degradation.

Flat spotting occurs when heavy weight sits on one section of tire for extended periods, deforming the internal steel belts and polymer casing. Severe cases cause permanent vibration. UV and ozone damage breaks down the rubber compounds (especially the anti-ozonants), causing sidewall cracking known as dry rot. These cracks weaken structural integrity and increase blowout risk.

Five-Step Prevention

1. Inflate to maximum sidewall pressure before storage to reduce flex and slow flat spotting
2. Place a barrier between tires and the ground. Plywood, leveling blocks or rubber mats prevent surface chemicals from leaching into the rubber
3. Cover tires with white or reflective vinyl covers to block UV radiation
4. Move the RV every 3 months if possible, rotating the tires 90 degrees to shift the contact point
5. Lighten the load by removing heavy items and emptying water tanks

Exterior Protection and Storage

Covers

An RV cover shields against snow, rain, UV and debris. Material matters:

• Polypropylene (e.g., ADCO SFS AquaShed): Good balance of water resistance and breathability. Works well in wetter climates.
• Tyvek (e.g., Camco UltraGuard): Outstanding UV resistance and durability. Nearly impermeable to water while still allowing vapor to escape. Ideal for snowy winters with intense sun.

Fit matters as much as material. Universal-fit covers billow in wind and abrade paint. Custom-fit covers follow your RV's contours and minimize movement. The higher cost prevents expensive paint and graphic damage.

Sealant Inspection

Water intrusion worsens dramatically through freeze-thaw cycles. Inspect and reseal before storage:

• Roof (EPDM/TPO): Use Dicor 501 self-leveling lap sealant on all seams, vents and accessories. Never use silicone-based sealant on EPDM or TPO roofs. It doesn't adhere properly.
• Vertical surfaces (windows, doors, corner moldings): Use Geocel ProFlex RV non-sag sealant. It stays in place without running, adheres to both fiberglass and aluminum, and remains flexible through temperature swings.
• Slide-out seals: Clean thoroughly and lubricate with rubber conditioner to prevent sticking, cracking and drying during storage.

Storage Site Selection

Park on firm, well-drained gravel or pavement. Grass traps moisture and promotes corrosion. Avoid parking under trees. Falling branches, sap and bird droppings all cause damage. Orient your RV to minimize wind load on the cover based on prevailing wind direction.

De-Winterization: Spring Recommissioning

When spring arrives, reverse the winterization process thoroughly before using your water system:

1. Flush antifreeze. Connect to a potable water source. Open every faucet (hot and cold) until water runs clear with no pink tint. Flush the toilet several times. Run the outdoor shower. Open low-point drains until clear water flows, then close them.

2. Sanitize the fresh water tank. Close the drain valve. Add 1/4 cup household bleach per 15 gallons of tank capacity. Fill the tank completely. Run the pump until you smell bleach at every faucet. Let it sit 4-12 hours. Drain completely, then refill and flush until the bleach smell is gone (may take multiple cycles).

3. Reinstall components. Replace the water heater drain plug or anode rod (use Teflon tape, torque to 7-8 ft-lbs). Install fresh water filter cartridges.

4. Reset bypass valves to normal operating position so water flows to the water heater.

5. Leak check. Turn on the water pump with all faucets closed. If the pump cycles on and off, there's a leak. Inspect every fitting, especially near the pump, toilet valve, faucets and under sinks. Address leaks immediately. Small drips become big problems.

Winter Living Modifications

For RVers who use their rig through winter rather than storing it, the approach shifts from decommissioning to active freeze prevention:

Skirting creates a thermal barrier around the underbelly. Foam board is the budget DIY option (high R-value, easy to cut). Custom snap-on vinyl provides a professional look. Inflatable AirSkirts offer the fastest setup for RVers who move frequently.

Heated hoses are mandatory when connected to city water in freezing conditions. Brands like Camco and NoFreeze protect supply lines down to -20°F or lower.

Tank heaters are 12V adhesive pads that go on the bottom of holding tanks, thermostatically controlled to prevent overheating. Cover as much tank surface as possible.

Propane planning: A 30,000 BTU furnace running continuously depletes a 30lb propane tank in roughly 18 hours. In extreme cold, budget for refills every 2-3 days. Having a backup tank on hand prevents uncomfortable surprises.

Solar in winter: Panels actually operate more efficiently in cold temperatures, but shorter days and lower sun angles reduce total output. Tilt panels to shed snow and maximize exposure. Supplement with shore power or a generator when solar production drops.

Getting Expert Help

Winterization doesn't have to be intimidating. Once you've done it once, the process takes a couple of hours and becomes routine. Your owner's manual is the best source for model-specific valve locations and procedures.

If you'd prefer professional help or have questions about your specific RV's winterization requirements, your local Jayco Family of Companies dealer has the expertise and equipment to handle the entire process. Find a dealer near you to schedule service or explore RV models with features that simplify winter maintenance.