How to Winterize an RV
Winterizing an RV means clearing water from the lines, tanks, and water heater, then protecting what's left with antifreeze made for RVs.
Drain the system, then protect it
Start by draining the fresh water tank, the gray tank, and the black tank completely. Open the low point drains and let gravity do the work, then pull the plug on the water heater and let it empty too. Once everything is dry, run RV antifreeze through the lines using either the water pump or a hand pump connected at the city water inlet, until it comes out pink at every faucet, the shower, and the toilet.
The reason for both steps is that water left in the lines expands when it freezes and splits pipes, fittings, and the water heater tank. Antifreeze alone doesn't help much if there's still water sitting in a line mixing with it. Drain first, then protect what's left.
What kind of water heater you have changes a step
Some RV water heaters have a bypass valve built into the plumbing. If yours does, close the valve settings so antifreeze doesn't fill the water heater tank itself. That tank holds a lot of water, and filling it with antifreeze wastes most of a jug for no benefit, since the tank doesn't hold water over winter anyway once it's drained.
If your rig doesn't have a bypass valve, you can install one, or you can skip that step and just use more antifreeze. Check the owner's manual or look at the plumbing near the water heater itself. It's usually a cluster of two or three valves close together.
Either way, make sure the pressure relief valve is closed and the drain plug is back in before you start running antifreeze, or it will run straight out onto the ground instead of through the lines.
What most people forget to drain
The water pump itself can trap water, and so can the low point drain lines if they loop or dip anywhere along their run. After the tanks are empty, open a faucet somewhere in the middle of the RV, like the kitchen sink, and let it run until air comes through, not just a trickle.
Ice maker lines, outdoor showers, and washing machine hookups are easy to miss because they're not part of the main faucet run. If your RV has any of these, they need their own antifreeze treatment or their own drain point.
The toilet and the holding tanks themselves also need a dose of antifreeze poured directly in, not just run through the lines, since they don't connect to the same supply path as the sinks.
Questions people ask about this
Can I use regular car antifreeze to winterize my RV?
No, regular automotive antifreeze is toxic and isn't made to go through a system you'll later drink from or wash with. RV antifreeze is propylene glycol based and is safe in a potable water system. Car antifreeze is ethylene glycol and should never be used this way.
How do I know if I got all the water out before adding antifreeze?
Run every faucet, inside and out, until no water comes out at all, including hot and cold settings on each one. Flush the toilet until it runs dry. If any water drips out after antifreeze is already in the lines, it will dilute it and reduce how much cold it can handle.
Do I need to winterize the fresh water tank itself or just the lines?
The tank should be drained completely along with the lines, since it's not usually filled with antifreeze. A low point drain at the bottom of the tank lets it empty fully. Leaving even a small amount of water in the bottom of the tank can cause it to crack if it freezes.
What happens if I don't winterize my RV at all one season?
Any water left in the pipes, water heater, or pump can freeze and crack them, and the damage often isn't visible until you use the system again and find a leak. The severity depends on how cold it gets and for how long the RV sits unused. Repairs to a cracked water heater or burst pipe usually cost far more than the antifreeze and time it takes to winterize.
Can I pay someone to winterize my RV instead of doing it myself?
Yes, many RV dealerships and service centers offer this as a seasonal service. It's worth asking what their process covers, including whether they check the water heater bypass and outdoor hookups specifically, since a rushed job can miss exactly the spots that freeze and crack.
If winterizing has you thinking about how your RV is insured for the off season, it's worth comparing coverage before the weather turns.
Pick a weekend before the first hard freeze is expected in your area, since timing matters more than the calendar date. Buy enough RV antifreeze for your size of rig, usually more than one jug, and have your owner's manual on hand for the water heater bypass valve. Walk through every faucet, the shower, the toilet, and any outdoor or specialty hookups so nothing gets missed. If you're not confident doing it yourself, call an RV dealership or service center and ask what their winterizing service includes.
