How to Winterize an RV: Step-by-Step With RV Antifreeze, the Water Heater Bypass, and How Many Gallons You Need

Water grows by about 9% when it freezes, and an RV is a box of thin plastic lines, brass valves and a pump that can split under it in one cold night. RV makers do not cover freeze damage under warranty. Winterizing takes an afternoon and, if your water heater is bypassed, 2 to 3 gallons of antifreeze.

This guide is for owners of travel trailers, fifth wheels and motorhomes who winterize the plumbing themselves. It covers when to do it, what you need, the air-versus-antifreeze choice, the step-by-step procedure, the water heater bypass, how much antifreeze to buy, the toilet, ice maker and washer, what RV antifreeze actually is, and how to bring the system back in spring. Every procedure is taken from RV and water-heater makers’ own manuals, and where those manuals disagree we say so.

We sell propylene glycol in USP Grade, from a 20% premix to 100% concentrate, which is the same glycol most pink RV antifreeze is built on. The chemistry of why it works, and the full freeze-versus-burst table, is in our propylene glycol freeze protection guide. This page is the hands-on procedure.

Last reviewed 28 October 2026 against the sources cited below. This is a practical maintenance guide, not medical, legal or regulatory advice. Your RV and appliance makers’ manuals win wherever they differ from this page. How we researched it is set out at the end.

How to winterize an RV at a glance

Drain everything, bypass the water heater, push antifreeze to every fixture, and put a cup in every trap. The table is the short version; each row is sourced in its own section below.

When should you winterize an RV?

Winterize at the end of the season, or before the RV will sit anywhere temperatures can reach 32 °F. Jayco’s owner’s manual puts it plainly: “The RV should be winterized at the end of the camping season or when it will be exposed to temperatures that will fall at or below 32°F (0°C). Repairs due to freezing are not covered by warranty.” Winnebago’s towables manual uses the same 32 °F line.

The trigger is the first night that can freeze, not the first cold week. A single clear, still night in October can drop a low spot in the yard below freezing while the daytime high is 50 °F, and the water trapped in a low-point drain or a pump head does not care what the forecast said for the afternoon. If you are storing the rig in a heated building all winter, you may not need antifreeze at all; if the building is unheated, you do.

What do you need to winterize an RV?

You need RV antifreeze, a way to get it into the water pump, and a few basic tools. Most of this kit is reusable for years.

• RV antifreeze: 2 to 3 gallons for the pump-in method with the water heater bypassed, per Winnebago’s manuals; more if you have a washer, a long rig or no bypass. Buy one extra jug.
• A pump converter (siphon) kit, or a factory winterizing valve at the pump, so the pump draws from the jug instead of the fresh tank.
• A water heater bypass, which most modern RVs have from the factory, or a bypass kit if yours does not.
• A blowout plug and an air compressor you can regulate to 30 psi, if you are blowing the lines out first.
• A socket for the water heater anode rod or drain plug (check your heater; Suburban uses an anode rod, many Atwood tanks a plastic drain plug).
• Gloves, a flashlight, rags and a bucket. RV antifreeze stains sinks if it dries, and Jayco recommends wiping it out of sinks, the tub and the toilet with a dry cloth.

Should you blow out RV lines with air, use antifreeze, or both?

Both, for an RV stored outdoors: blow the water out first, then pump antifreeze through. Jayco’s manual is clear that air alone is not enough for unheated storage: “the air pressure method is not adequate, winterizing with RV antifreeze must be used in the plumbing system.” Camping World’s guide says the same, that compressed air alone “is not recommended as a standalone winterization method for most owners.”

The important point is that winterizing is mostly about removing water, not adding antifreeze. Antifreeze only protects the places it reaches, at the strength it arrives. Every cup of water left in a line, a pump head or a valve body dilutes it, and a pocket it never reaches is a pocket of plain water waiting for the first hard frost.

The reason is the water you cannot see. Air clears most of each line, but water collects in low elbows, valve bodies, the pump head and fixtures, and those are the places that crack. Antifreeze pushed in after the air reaches those pockets. Blowing out first is still worth doing, because every cup of water left in the lines dilutes the antifreeze that follows it.

How do you winterize an RV with antifreeze? Step by step

Drain first, bypass the heater second, pump antifreeze third, and finish with the traps. This is the pump-in method in the order Jayco and Winnebago give it; your manual may name valves differently.

1. Turn off the water heater and let it cool. Switch off electric and gas. Winnebago warns to drain the tank “only when the tank water is cold”, and Suburban notes hydrogen gas can collect in a heater that has sat unused, so open a hot faucet and keep flames away.
2. Disconnect city water, level the RV and empty the holding tanks. Dump and flush the black and gray tanks first. Winnebago points out that if the coach is not level, low points can trap water in the lines.
3. Remove the water filter. Jayco says the filter “should be removed for winterizing” and replaced in spring. Fit the bypass hose in its place.
4. Drain the fresh tank, the low-point drains and the water heater. Open every faucet, inside and out. Remove the water heater’s anode rod or drain plug and open its pressure-relief valve so the tank drains without air-locking.
5. Blow out the lines (optional but worth it). Fit a blowout plug to the city water inlet and regulate the compressor to 30 psi or less. Open each fixture in turn until only air comes out. Winnebago advises letting air in slowly rather than in a burst.
6. Close every drain and put the water heater in bypass. Close the low-point drains and the fresh tank drain, refit the anode rod or drain plug, and turn the bypass valves to BYPASS. Jayco: “Antifreeze should never enter the hot water heater or the water filter.”
7. Connect the pump to the antifreeze. Set the pump’s winterizing valve, or attach a converter kit, and put the tube in the jug. Jayco suggests standing the jug about 2 feet off the ground to help the siphon.
8. Turn on the pump and open each faucet, one at a time, hot then cold. Start with the fixture farthest from the pump. Close each one when antifreeze flows steadily. Do the outdoor shower and outdoor kitchen too.
9. Flush the toilet until antifreeze reaches the bowl, and leave a little in the bowl to keep the seal wet, as Winnebago’s towables manual advises.
10. Open the low-point drains briefly until antifreeze appears, then close them quickly, so the lowest lines hold antifreeze rather than water.
11. Pour about a cup of antifreeze into every drain: kitchen sink, bathroom sink, shower or tub, and the washer drain if you have one.
12. Turn off the pump, relieve the pressure and wipe up. Thor’s guide suggests leaving faucets half open in storage to take the load off the valve seats. Wipe antifreeze out of sinks and the toilet so it does not stain.

Do you need to bypass the water heater when winterizing an RV?

Yes. Drain the water heater and put it in bypass so antifreeze never enters it. The heater maker’s reason is the anode rod. Suburban’s manual says to “leave the water heater closed off (out of the system) in the bypass position particularly if you are introducing antifreeze into the plumbing system. Antifreeze can be very corrosive to the anode rod creating premature failure and heavy sediment in the tank.” If your system has no bypass kit, Suburban says to remove the anode rod for the winter and fit a 3/4-inch drain plug in its place.

The second reason is volume. Airstream notes that bypassing “saves you the six gallons of RV antifreeze needed to fill the hot water heater.” Good Sam puts the waste at “six or ten gallons” depending on the tank.

Not every source agrees on the corrosion point: Grand Design’s owner article says antifreeze “will not damage your hot water heater” and frames the bypass as saving fluid. We side with the appliance maker, Suburban, because it is their tank and their warranty. Two other notes from the manuals:

• Tankless heaters have their own procedure. Truma says its AquaGo “can be fully winterized without any chemicals” using its drain lever, and does “not recommend the use of high-pressure air or antifreeze solutions” except with an installed bypass kit.
• Bypass position during an air-only blow-out varies by maker. Jayco and Winnebago’s Vista manual keep the bypass in NORMAL while blowing out and switch to BYPASS only for antifreeze; Forest River and Keystone set BYPASS for both. Follow your own manual.

What PSI should you use to blow out RV water lines?

Use 30 psi or less unless your manual says otherwise. Jayco: “Recommended pressure is 30 PSI, exceeding this pressure may rupture water line couplings and void your warranty.” Winnebago, Forest River and Keystone give the same 30 psi ceiling, and Winnebago’s 2025 towables manual goes lower, to “around 20lbs psi.”

Airstream’s blog is the outlier, saying to keep air pressure “under 60 psi.” That is Airstream’s number for Airstream plumbing. For any other rig, 30 psi is the figure the makers agree on. Never apply air with valves closed: Jayco warns that air against a closed valve, faucet or low-point drain can damage seals.

How many gallons of antifreeze does it take to winterize an RV?

Two to three gallons for the pump-in method with the water heater bypassed, according to both of Winnebago’s 2025 manuals, one for a travel trailer and one for a Class A motorhome. The real number depends on the method, the length of the rig and how many water-using appliances it has.

Go RVing, the RV industry’s consumer site, puts the typical range at “two to four gallons.” Washers, dishwashers and long bunkhouse plumbing push you to the top of it.

Do you put antifreeze in the RV fresh water tank?

Normally no. Drain the fresh tank and pump antifreeze from a jug through a converter kit instead. Filling the tank wastes antifreeze, because the pump cannot pick up the first several gallons, and you then have to flush all of it out in spring. Camping World puts that dead volume as high as 10 gallons in a tank with a side pickup. Pour into the tank only if your rig gives you no other way to feed the pump, which is why Forest River, Thor and Keystone include it as a method.

How do you winterize the toilet, ice maker, washer and outdoor shower?

Every fixture that holds water needs antifreeze or a full drain, and the manuals list them one by one because they are the ones people forget.

• Toilet: hold the flush lever until antifreeze reaches the bowl. Keystone allows about a quart into the black tank and leaves a little in the bowl to cover the seals.
• Outdoor shower and outdoor kitchen: run hot and cold until antifreeze flows, and run the shower diverter and hose too. Winnebago: “Make sure to turn on both hot and cold knobs.”
• Ice maker: the manuals disagree. Keystone says if you have a residential refrigerator, “do not add antifreeze to the ice maker water line” and to drain it instead; Thor’s guide includes ice makers in the antifreeze run. Follow your refrigerator maker’s instructions; Jayco says appliances “must be winterized” and to check their own manuals.
• Washing machine: Keystone runs the fill cycle on cold until antifreeze appears, then on hot, and pours antifreeze into the washer drain.
• Water pump strainer: Winnebago says to empty the strainer bowl “to avoid water freezing and cracking the filter bowl.”
• Black tank flush and city water inlet: blow these out with air at 30 psi or less, then push the inlet’s check valve until antifreeze shows, as Grand Design describes.

Can you use propylene glycol instead of RV antifreeze?

Yes. Most pink RV antifreeze is propylene glycol and water with a dye, and a USP-grade propylene glycol premix does the same job. Here is what the safety data sheets of common “−50 °F burst” products actually list:

From each product’s published SDS; formulations change, so read the current sheet for the jug you buy. Camco’s Arctic Ban sheet lists a freeze point of −20 °F next to its −50 °F burst rating.

Two things stand out. First, the “−50 °F” on the jug is a burst rating, not a freeze rating. Star brite defines it: a product “labeled with a burst protection of -50°F may start to freeze at a higher temperature, but it won’t expand enough to damage a copper pipe until it reaches -50°F.” The fluid turns to slush long before that; the promise is that the lines survive. Second, not every pink jug is glycol. Ethanol blends are flammable, and Camping World says they “can dry out seals” and leave a strong taste or smell.

Which concentration? Dow’s published engineering table for propylene glycol solutions gives burst protection to about −20 °F at 30% glycol by volume and below −60 °F at about 50%. That table, and why more glycol is not better above about 60%, is laid out in our freeze protection guide. For most of the country a 30% premix is the practical choice; for northern storage, step up to 40% or 50%. If you buy 100% concentrate, dilute it to the target yourself with clean water.

Which grade? USP Grade, for any fresh-water line. Our inhibited propylene glycol carries a corrosion-inhibitor package meant for closed heating and cooling loops, and Technical Grade is for equipment that will be flushed before use. Neither belongs in RV fresh-water plumbing. The USP products we sell for this job:

Why should you never use car antifreeze in an RV?

Because automotive antifreeze is ethylene glycol, which is poisonous if swallowed, and your fresh-water lines feed the kitchen faucet. Winnebago’s manual: “Never use automotive antifreeze/coolant in your RV water system. Auto antifreeze contains ethylene glycol which, if ingested, can cause blindness and can be fatal.” Jayco adds windshield washer fluid to the list: “Automotive antifreeze (ethylene glycol) and windshield washer antifreeze (methanol) are poisonous. Never use these products in your fresh water system.”

The CDC’s toxic substances agency explains why it is so dangerous: “Accidental or intentional ingestion can occur because antifreeze is a sweet tasting, brightly colored liquid,” and ingesting larger amounts “can cause serious illness or death.” Propylene glycol is the glycol the FDA lists as generally recognized as safe for use in food, at limited levels, which is why it is the one used in RV plumbing. That is not a reason to drink it: flush the system thoroughly before you use the water in spring. Our propylene glycol vs ethylene glycol guide covers the two molecules side by side.

How do you de-winterize an RV in spring?

Flush every line with fresh water until it runs clear, put the water heater back in service, then give the fresh-water system the chlorine flush your RV maker describes. The order, condensed from Forest River, Keystone and Winnebago:

1. Close the drains and refit the anode rod or drain plug. Keystone: “Insert the anode rod or tank plug first.” Suburban recommends replacing the anode yearly.
2. Fill the fresh tank or connect city water, turn on the pump, and check fittings for leaks.
3. Run every faucet, hot and cold, plus the shower, outdoor shower and toilet, until the water runs clear with no trace of antifreeze. Open the low-point drains until they run clear, then close them.
4. Take the water heater out of bypass and run a hot faucet until the tank is full and air stops sputtering, before you turn on gas or electric.
5. Chlorine-flush the fresh-water system. Jayco, Winnebago and Forest River all give the same household-bleach recipe: 1/4 cup of bleach to one gallon of water, one gallon of that solution for every 15 gallons of tank capacity, for a residual of about 50 ppm chlorine. Contact time varies by manual, from at least 3 hours (Forest River) to 4 hours (Jayco, Winnebago Vista); Jayco allows 1 hour at 100 ppm. Then flush until there is no chlorine odor.
6. Fit a new water filter. Jayco says to replace it at the start of each season or after contact with antifreeze.

What are the most common RV winterizing mistakes?

Almost every spring repair story starts with water that was still somewhere when the antifreeze went in.

• Skipping the low-point drains. They are the lowest water in the system. Drain them, and run antifreeze to them at the end.
• Forgetting the bypass. You fill a six-gallon tank with antifreeze, run out before the lines are done, and expose the anode rod Suburban warns about.
• Running only the cold side. Winnebago’s blog notes that hot and cold need to be done separately, even on a single-handle faucet.
• Too much air pressure. Over 30 psi can split couplings, and Jayco says it can void your warranty.
• Running the pump dry too long. Jayco warns that running the pump dry longer than about 15 to 20 seconds can damage it.
• Missing a fixture. Outdoor shower, outdoor kitchen, washer, ice maker line, pump strainer bowl and toilet are the usual suspects.
• Using car antifreeze or washer fluid. Ethylene glycol and methanol do not belong anywhere near fresh-water lines.
• Not checking the jug. An ethanol blend is flammable. If you want propylene glycol, read the SDS, not the color.

Key numbers and sources