Quick answer: Here is how to winterize an RV: drain and flush the tanks, drain and bypass the water heater, drain the lines, remove or bypass the filter, run non-toxic RV antifreeze through every fixture, then fill the P-traps. Do it before temperatures reach 32°F. Your owner’s manual overrides any general guide.
How do you winterize an RV?
The proper way to winterize an RV is to remove as much water as you can, then protect what remains with RV antifreeze. In the 10-step sequence below, steps 1-5 empty the system and steps 6-10 add the antifreeze.
When to do it: Jayco advises winterizing at the end of the camping season or before exposure to temperatures at or below 32°F (0°C).
Why it matters: Freeze damage can be expensive to repair, and warranty coverage may not help. Jayco states that freeze damage repairs are not covered under its Towable Limited Warranty. Check your own warranty before you assume yours is different.
Which instructions win: Valve layouts and procedures vary by model, so your owner’s manual overrides this guide. Use the decision rules below when your manual and a general guide don’t match.
What supplies do you need to winterize an RV?
Most of the job takes a few basic items. Which ones you need depends on your heater and plumbing setup.
| Item | Purpose | When it is needed |
|---|---|---|
| Non-toxic RV antifreeze | Protects water lines, fixtures and traps | Always |
| Siphon kit | Draws antifreeze from the jug at the water pump | If you use the pump method and have no built-in siphon |
| Water heater bypass kit | Keeps antifreeze out of the heater tank | If the RV has no working bypass |
| Socket | Removes the heater drain plug or anode | If the RV has a tank-style heater |
| Potable-rated thread tape | Seals the plug threads | When you reinstall a threaded plug or anode |
| Hoses | Flush the black tank or connect antifreeze to the city water fill | When your procedure calls for them |
| Flashlight | Helps you find valves and drains and check fixtures | Always |
Camping World says water heater drain plug or anode sockets are typically 1-1/16, 7/8 or 15/16 inch. Check the size before you start.
Buy spare antifreeze too. Running out halfway through can leave some fixtures unprotected.
How much RV antifreeze do you need?
Most RVs need 2-4 gallons of RV antifreeze when the water heater is bypassed, and larger rigs may need more. Camping World’s supply list calls for 3-4 gallons, with extra recommended.
Plan for these extras:
- Sink and shower drains: Camping World recommends 1-2 cups per drain. Jayco’s air method specifies one cup per P-trap.
- Black tank: Camping World recommends about half a gallon through the toilet, leaving 3-4 inches in the bowl.
Decision rule: Count your bathrooms, outside showers and water-using appliances, then round up. For example, a kitchen sink, bathroom sink and shower need 3-6 cups at Camping World’s rate. Add 8 cups for the black tank, and the drains and toilet use 11-14 cups, just under one gallon.
Don’t skip the bypass. Without it, antifreeze fills the heater tank before it does any useful work in the lines, and you will need far more of it.
Which RV antifreeze should you buy?
Use only non-toxic RV antifreeze in the fresh water system. You cannot use regular car antifreeze in an RV. Jayco warns that automotive and windshield washer antifreeze are poisonous and should never be used in the fresh water system.
Burst point vs freeze point
Freeze point is the temperature at which a fluid starts to turn to slush or ice. Burst point is the temperature at which freezing fluid is claimed to expand enough to damage plumbing.
Practical Sailor calls burst point a fuzzy term with no industry-accepted standard test. It reports that -50 products contain about 30 percent glycol, while -100 products generally contain about 60 percent. That testing covers marine systems, so it applies to RV plumbing by analogy.
The trade-off: A -50 label is a burst rating, not a promise that the fluid stays liquid at -50°F. If you store the RV in a very cold region, or parts of the system can’t be fully drained, a stronger product may be worth buying. Use antifreeze straight from the jug and do not dilute it.
Propylene glycol vs ethanol-based products
Practical Sailor describes propylene glycol as relatively non-toxic and suitable for potable water systems. Make it your default choice.
If a jug lists ethanol, alone or in a blend, check that the label says it is safe for potable water systems. If the label doesn’t say so, leave it on the shelf.
How do you drain an RV before adding antifreeze?
Drain the heater, tanks and lines first, because any water left behind dilutes the antifreeze. Disconnect city water and turn off the pump before you begin.
Drain and bypass the water heater
Yes, you need to drain a tank-style water heater when you winterize. Antifreeze won’t protect it once it is bypassed, so any water left inside can freeze.
- Prepare the system and shut down the heater. If you follow Camping World’s method, put 5-10 gallons of water in the fresh tank for flushing. Turn off the water heater and let it cool. Turn the breaker off for electric heat, or close the propane container valves for gas.
- Drain the heater. Remove the drain plug or anode, open the pressure relief valve, and let the tank drain fully. Then set the bypass valves. Tiffin says to activate the bypass so antifreeze does not fill the heater.
Warning: Never drain a hot or pressurized water heater. Tankless heaters have different procedures, so follow the manufacturer’s instructions for those units.
Empty the holding and fresh tanks
- Empty the holding tanks. Dump the black tank first, then the gray tank. Flush the black tank and close the gate valves.
- Drain the fresh tank. Open its drain and let the tank empty.
In this sequence, you don’t put antifreeze in the fresh water tank. You drain the tank and send antifreeze directly into the lines. If your manual gives a different method, follow the manual.
Open the low-point drains
Low-point drains are valves or caps at the lowest part of the hot and cold water lines. Their location varies by model, so check your manual if you can’t find them.
- Clear the lines and filter. Open the low-point drains and run the pump only briefly to clear it, shutting it off once the water stops. Remove any inline filters. If your RV has a bypass hose for the filter housing, install it now.
How do you run antifreeze through RV water lines?
Close the drains, connect the antifreeze supply, and open each fixture until antifreeze flows continuously. Work on the hot side first and then the cold side at each faucet.
- Set up the system. Confirm the heater bypass is set and the heater switches are off. Close the low-point and fresh tank drains.
- Connect the antifreeze supply. Use the setup your manual specifies. The two common options are compared below.
- Run every fixture. Open each faucet on the hot side, then the cold side, until antifreeze flows continuously. Include the shower, outside shower and toilet.
- Protect the drains. Pour antifreeze into each P-trap, which is the curved pipe that holds water below a drain. Add it to the washer or dishwasher drains if equipped. Then add the black tank portion through the toilet.
- Close up. Close the faucets and re-cap the drains. Jayco says to wipe antifreeze from sinks, showers, tubs and toilets with a soft, dry cloth to prevent staining.
| Setup | How it works | Use it when |
|---|---|---|
| Siphon kit at the pump | A tube at the water pump draws antifreeze from the container | Your manual uses the pump method or your RV has a siphon valve |
| Hose to the city water fill | A hose connects the antifreeze container to the city water fill, as in Jayco’s demand or power plumbing procedure | Your manual specifies this procedure |
Decision rule: Match the setup to the plumbing type listed in your manual. If you can’t identify the type or the manual is missing, contact the manufacturer or an RV service shop before you connect anything.
Should low-point drains be open or closed?
Keep low-point drains open while draining water and closed while running antifreeze. Jayco’s procedure closes them before antifreeze goes in. On Jayco Motorized products, they must be closed for antifreeze to siphon through the lines, and the heater valves are set to “Sanitize/Winterize Lines.”
If antifreeze won’t reach a faucet, check the low-point drains first. Valve labels and positions vary, so go by the wording in your manual.
Do not forget these easy-to-miss fixtures
- Outside shower, both hot and cold
- Indoor shower, both the faucet and the drain trap
- Toilet supply line, which is easy to overlook
- Washer and dishwasher drains, which Tiffin says need antifreeze to protect their hidden traps
- Any other appliance connected to water, following its own manual
What mistakes cause freeze damage after winterizing?
Most freeze damage comes from water left somewhere in the system or from a fixture that antifreeze never reached.
| Mistake | Result | Fix |
|---|---|---|
| Water heater left undrained | Water in the bypassed tank can freeze | Cool it, remove the plug or anode, and drain it fully |
| Filter left in line | Water stays in the housing, and antifreeze can end up in the cartridge | Remove the filter and install the bypass hose if equipped |
| Outside shower skipped | Water stays in the exposed fixture and its lines | Run hot and cold until antifreeze flows continuously |
| Low-point drain in the wrong position | Antifreeze leaks out or won’t draw through the lines | Open them to drain and close them before adding antifreeze |
| Water left in the lines | Antifreeze is diluted and loses protection | Drain the tank, heater and lines first |
Pink fluid confirms that antifreeze reached a fixture, as in Tiffin’s run-until-pink instruction. It doesn’t measure strength. Practical Sailor says color is a poor indicator of antifreeze strength and that undrained water dilutes the product, so draining first is the best way to limit dilution.
What else should you do before storing an RV for winter?
Once the plumbing is protected, finish these storage tasks, based on Tiffin’s storage guidance:
- Remove or disconnect the house batteries, or keep them on a maintenance charger.
- Check tire pressure.
- Inspect the roof seals and reseal where needed.
- Screen exterior vents.
- Find and block rodent entry points.
Battery storage needs differ between lithium and lead-acid types, so follow the instructions from your battery’s maker.
Should you learn how to winterize an RV yourself or pay a shop?
DIY suits owners who can reach their valves and have a working water heater bypass. If you can find every drain and your manual covers your plumbing type, this is a manageable job.
Consider a shop if any of these apply:
- The RV has a washer, dishwasher or residential fridge.
- It has a tankless water heater.
- You can’t find the valves or low-point drains.
Prices vary, so request a local quote. Ask what the service includes, especially the appliances and outside fixtures on your rig.
Frequently Asked Questions About Winterizing an RV
At what temperature should I winterize my RV?
Winterize your RV before temperatures reach 32°F (0°C). Jayco advises doing it at the end of the camping season or before any exposure to temperatures at or below 32°F. Water left in the lines, water heater or fixtures can freeze, and the repairs can be expensive and may not be covered by warranty.
Do you put antifreeze in the RV fresh water tank?
No, in the standard drain-and-bypass method you do not put antifreeze in the fresh water tank. You drain the tank, then send RV antifreeze directly into the water lines, using a siphon kit at the pump or a hose at the city water fill. If your owner’s manual gives a different method, follow the manual.
Do you need to drain the water heater when winterizing an RV?
Yes, you need to drain a tank-style RV water heater when winterizing. Antifreeze won’t protect it once it is bypassed, so any water left inside can freeze. Let the heater cool, remove the drain plug or anode, open the pressure relief valve, and drain it fully. Tankless units have different procedures, so follow the manufacturer’s instructions.
How much antifreeze goes in RV drains and the toilet?
Camping World recommends 1-2 cups of RV antifreeze per sink or shower drain and about half a gallon through the toilet into the black tank, leaving 3-4 inches in the bowl. Jayco’s air method specifies one cup per P-trap. A kitchen sink, bathroom sink, shower and toilet together use just under one gallon.
Can you use regular car antifreeze in an RV?
No, you cannot use regular car antifreeze in an RV’s fresh water system. Jayco warns that automotive and windshield washer antifreeze are poisonous and should never be used there. Use only non-toxic RV antifreeze, with propylene glycol as the default choice, and pour it straight from the jug without diluting it.
