Quick answer: to winterize an RV, empty and flush the holding tanks, drain the fresh water tank and water heater, open the low-point drains, put the water heater in bypass, then either pump non-toxic RV antifreeze (propylene glycol, never automotive antifreeze) through every faucet, the toilet and the outdoor shower until it runs pink, or blow the lines out with compressed air at low pressure. Pour antifreeze into each drain trap, remove filter cartridges, and finish by caring for batteries, propane, tires and pest-proofing. Always follow your RV manufacturer’s manual, since plumbing layouts differ.
Water expands as it freezes, by roughly 9 percent, and that is enough to split RV water lines, crack fittings and ruin a water heater tank or pump. Repairs can be expensive and often go unnoticed until the first spring trip, when water starts leaking behind a cabinet.
Winterizing protects the plumbing and the rest of the rig while it sits through cold months. This guide covers both common methods step by step, plus storage tasks and spring de-winterizing. For a broader introduction to RV systems, costs and campgrounds, see our RV camping for beginners guide.
Sources: RV Industry Association (RVIA) consumer resources; RV owner’s manuals and water heater manufacturer manuals (Suburban, Dometic); U.S. Geological Survey (USGS) Water Science School on the properties of ice; battery manufacturer guidance on cold-weather charging; U.S. Fire Administration RV fire safety; Centers for Disease Control and Prevention (CDC) on disinfecting water systems. Checked October 2026.
When Should You Winterize an RV?
Winterize before overnight temperatures start dropping below freezing where the RV is stored. A single hard freeze can damage exposed plumbing, so many owners winterize in the fall as soon as the camping season ends rather than waiting for the forecast.
If you camp in winter
If you plan to keep using the RV in cold weather, winterizing is not practical between trips. Instead, owners rely on heated, enclosed underbellies, tank heaters, heated hoses and keeping the furnace running. Check whether your rig is rated for four-season use and follow the manufacturer’s cold-weather guidance.
Two Ways to Winterize
There are two common methods. Many owners combine them, blowing the lines out first and then adding antifreeze to traps and the toilet.
| Method | How it works | Pros | Cons |
|---|---|---|---|
| RV antifreeze | Replace water in lines with non-toxic propylene glycol antifreeze | Thorough; no compressor needed | Costs a few gallons of antifreeze each year; must be flushed in spring |
| Compressed air blowout | Push water out of lines with low-pressure air | Little or no antifreeze in the lines; quicker spring startup | Needs a compressor and blowout plug; small pockets of water can remain |
Choosing the right antifreeze
Use only RV and marine antifreeze labeled for potable water systems, usually pink and based on propylene glycol. Never use automotive antifreeze, which contains toxic ethylene glycol. Check the label’s burst protection rating against the coldest temperatures in your area.
Tools and Supplies
Gather everything before you start so the job goes smoothly.
- RV antifreeze (often two to three gallons with the water heater bypassed; larger rigs may need more)
- Water heater bypass kit, if your RV does not already have bypass valves
- Pump converter kit or hand pump, or a compressor with a blowout plug for the city water inlet
- Wrench or socket for the water heater drain plug or anode rod
- Gloves and eye protection
- Owner’s manual for your RV and water heater
- Tank flushing wand or built-in black tank flush
Step-by-Step: The Antifreeze Method
Plumbing layouts vary by model, so treat this as a general sequence and match each step to your manual.
1. Empty and flush holding tanks
Dump the black tank first, then the gray tank, at a dump station or sewer hookup. Flush the black tank with the built-in flush or a wand until the water runs clear. Close the valves afterward.
2. Remove water filters
Take out any inline or under-sink water filter cartridges and install bypass hoses if your system calls for them. Antifreeze can damage filters, and filters left wet can crack.
3. Drain the fresh water tank
Open the fresh tank drain and let it empty completely. Turn off the water pump.
4. Drain the water heater
Turn off the water heater’s gas and electric power and let it cool completely; hot water and pressure can cause burns. Open the pressure-relief valve to release pressure, then remove the drain plug or anode rod (your water heater manual says which yours uses). Let the tank drain fully. Many owners inspect the anode rod at this point and replace it if heavily corroded.
5. Open low-point drains
Find the hot and cold low-point drain lines, usually under the RV near the fresh tank. Open them and let the lines drain. Opening all faucets at the same time helps the water flow out. Close the drains and faucets when finished.
6. Bypass the water heater
Set the water heater bypass valves so antifreeze skips the tank. Otherwise you would need to fill the whole water heater, often 6 to 10 gallons, with antifreeze.
7. Pump in antifreeze
Use the pump converter kit to draw antifreeze from the jug through the RV’s water pump, or use a hand pump connected to the city water inlet. Turn on the water pump.
8. Open each faucet until it runs pink
Starting with the fixture closest to the pump and working out to the farthest, open the hot side until pink antifreeze flows, then the cold side. Repeat at every sink, the shower, the outdoor shower and any other water outlet. Flush the toilet until antifreeze appears in the bowl.
9. Treat drains and traps
Pour a cup or two of antifreeze into each sink and shower drain to protect the P-traps, and a little into the toilet bowl to protect the seal. Some owners add a small amount to the holding tanks as well.
10. Handle appliances
Ice makers, washing machines, dishwashers and some refrigerator water lines need their own winterizing steps. Follow each appliance manual.
11. Close the city water inlet
Briefly press the check valve in the city water inlet until antifreeze appears, then cap it. Turn off the water pump and leave a note on the faucet reminding you the system is winterized.
Step-by-Step: The Compressed Air Method
The blowout method pushes water out with air instead of replacing it with antifreeze.
- Empty tanks, drain the water heater and open low-point drains, as above.
- Put the water heater in bypass.
- Remove water filters.
- Attach a blowout plug to the city water inlet and connect the compressor.
- Set the regulator to a low pressure; many RV manufacturers recommend staying below the water system’s rated pressure, which is often around 40 to 60 psi. Check your manual.
- Open one faucet at a time, hot then cold, until only air comes out. Repeat for every fixture, the toilet valve and the outdoor shower.
- Repeat the cycle a second time to clear remaining water.
- Pour antifreeze into each drain trap and the toilet bowl.
Water left in the pump can freeze, so many owners still run a small amount of antifreeze through the pump even after blowing out the lines.
Protect the Rest of the RV
Plumbing is the priority, but other systems also need attention before storage.
Batteries
Batteries slowly discharge in storage, and a discharged lead-acid battery can freeze and crack at temperatures a fully charged one survives. Either remove batteries and store them charged in a cool, dry place, or keep them on a maintenance charger. Turn off the battery disconnect to stop small parasitic loads. Lithium batteries have their own rules; many should not be charged below freezing, so follow the battery manufacturer’s guidance. Our guide to portable power for camping explains battery basics.
Propane
Close the valves on propane tanks or cylinders. Portable cylinders can be removed and stored upright outdoors, away from living spaces, following local rules. Do not store propane cylinders indoors.
Pests
Mice and insects look for warm, sheltered places in winter.
- Remove all food, including sealed packages.
- Clean the fridge, prop the door open and leave it off.
- Seal openings around pipes and wiring with appropriate materials.
- Cover furnace and water heater vents with screens designed for RVs, and remove them before using those appliances.
Moisture and mold
Closed-up RVs can trap moisture. Leave cabinets slightly open, use moisture absorbers, and consider a small dehumidifier if stored with power. Check periodically for leaks.
Roof, seals and exterior
Inspect the roof and seams for cracks and reseal as needed before snow arrives. Wash the RV to remove dirt and bugs, and close all windows, vents and awnings.
Tires
Inflate tires to the recommended pressure, cover them to block UV light and consider parking on boards or pads rather than bare ground. Chock the wheels.
Storage Checklist
- Holding tanks emptied, flushed and valves closed
- Fresh tank and water heater drained; water heater in bypass
- Lines filled with RV antifreeze or blown out
- Antifreeze in drain traps and toilet bowl
- Filters removed
- Batteries charged, disconnected or on a maintainer
- Propane valves closed
- Food removed, fridge open and clean
- Vents screened and openings sealed
- Roof and seals inspected
- Tires inflated, covered and chocked
- Note on the faucet: “Winterized”
How to De-Winterize in Spring
When warm weather returns, reverse the process and sanitize the water system before drinking from it.
- Reinstall the water heater drain plug or anode rod, and close low-point drains.
- Connect to city water or fill the fresh tank, and run every faucet until the water runs clear with no pink color or smell.
- Take the water heater out of bypass, let it fill completely with water and only then turn on the gas or electric element. Heating an empty tank can damage it.
- Reinstall water filters.
- Sanitize the fresh water system using the chlorine bleach method in your owner’s manual, let it sit for the recommended time, then drain and flush until the chlorine smell is gone.
- Check for leaks under sinks, around the pump and at the water heater.
- Test the batteries, propane system, smoke alarm, carbon monoxide alarm and LP gas detector.
Starting the season with a careful check prevents many of the problems covered in RV first-trip mistakes and how to avoid them, and our printable RV camping checklist helps you pack for the first trip.
Common Winterizing Mistakes
- Forgetting to bypass the water heater and wasting gallons of antifreeze
- Using automotive antifreeze in the fresh water system
- Missing the outdoor shower, toilet or ice maker line
- Leaving water filter cartridges in place
- Skipping the drain traps
- Turning on the water heater in spring before it is full
- Letting batteries discharge over winter
Frequently Asked Questions
What temperature should you winterize an RV?
Winterize before overnight temperatures fall below freezing where the RV is stored. Many owners winterize at the end of the camping season to avoid being caught by an early freeze.
How much RV antifreeze do I need to winterize?
Many RVs need about two to three gallons when the water heater is bypassed, but larger rigs with more fixtures may need more. Check your owner’s manual.
Can I use car antifreeze in my RV?
No. Use only non-toxic RV and marine antifreeze labeled safe for potable water systems. Automotive antifreeze contains toxic ethylene glycol.
Is it better to blow out RV lines or use antifreeze?
Both methods work. Antifreeze is more thorough, while blowing out lines avoids antifreeze in the plumbing. Many owners blow out the lines and still add antifreeze to traps, the toilet and the pump.
Do I need to winterize an RV if I live in a warm climate?
If temperatures where you store the RV never drop to freezing, full winterizing may not be necessary, but it is still smart to drain the system for long storage and follow the manufacturer’s guidance.
How do I de-winterize my RV?
Flush antifreeze out of the lines, take the water heater out of bypass and fill it before turning it on, reinstall filters, sanitize the fresh water system following your manual and check for leaks.
Sources
- RV Industry Association. Consumer RV maintenance resources.
- RV owner’s manuals and water heater manuals (Suburban, Dometic).
- U.S. Geological Survey, Water Science School. Ice and the density of water.
- Battery manufacturers. Cold-weather charging and storage guidance.
- U.S. Fire Administration. RV fire safety.
- Centers for Disease Control and Prevention. Disinfecting water systems.
