Learning how to winterize RV water system properly is the best way to prevent a massive plumbing headache when you pull your rig out of storage next spring. If you've ever seen what happens to a PEX pipe or a plastic water pump after a hard freeze, you know it isn't pretty. Ice expands, plastic cracks, and suddenly you're looking at a thousand-dollar repair bill for something that could have been avoided with about an hour of work and a few gallons of the "pink stuff."
Let's be honest, nobody actually enjoys winterizing. It usually happens right when the weather starts getting miserable, and you're already bummed out that camping season is over. But if you live anywhere where the temperature dips below 32°F, you really don't have a choice. Whether you're a seasoned pro or this is your first winter with a camper, getting the water out of those lines is the most important maintenance task on your to-do list.
Why you can't just skip this step
It's tempting to think that if you live in a place like North Carolina or Tennessee, you might be able to get away with just "winging it." Maybe you'll just run a small space heater inside the RV, right? Don't do it. Space heaters fail, power goes out, and even if the cabin stays warm, the pipes tucked away in the underbelly or behind cabinets are still vulnerable to the cold.
When water freezes, it expands by about 9%. That doesn't sound like much until you realize that water is trapped in a rigid pipe with nowhere to go. It'll blow the end caps right off your manifold or shatter your expensive water pump housing. Taking the time to learn how to winterize RV water system saves your wallet and your sanity.
Getting your supplies ready
Before you start, gather everything you need so you aren't running back and forth to the hardware store. You generally have two ways to do this: the compressed air method or the antifreeze method. Most people (myself included) prefer a combination of both for peace of mind.
Here is what you'll likely need: * Non-toxic RV Antifreeze: Make sure it's the pink stuff specifically labeled for RV/Marine use. Do not use automotive antifreeze; it's literal poison and will ruin your fresh water system forever. You'll usually need 2 to 3 gallons. * A Water Heater Bypass Kit: Most modern RVs have these built-in, but if yours is an older model, you might need to install one. * A Blowout Plug: This is a small brass or plastic fitting that screws into your city water inlet so you can hook up an air compressor. * An Air Compressor: You don't need a massive industrial one, but it needs to have a steady flow. * Basic Tools: A wrench or socket for your water heater drain plug.
Step 1: Drain the main tanks
The first thing you want to do is empty everything out. Head to a dump station one last time and empty your gray and black tanks. Give the black tank a really good flush so no "surprises" sit in there all winter.
Once those are empty, open up your fresh water tank drain. This is usually a white plastic valve underneath the rig. While that's draining, find your low point drains. These are usually two pipes (one red, one blue) hanging down under the RV with caps or valves on them. Open them up and then go inside and open all your faucets to help gravity pull the water out. Don't forget the outside shower if you have one!
Step 2: Tackle the water heater
This is where people usually mess up. Never drain the water heater while it's hot or under pressure. Turn off the electric and gas switches, let it cool down, and then open the pressure relief valve at the top. Once the pressure is hissed out, unscrew the drain plug at the bottom.
If you have a Suburban brand water heater, that plug is probably attached to an anode rod. If the rod looks like a chewed-up piece of wire, now is a great time to buy a replacement for the spring. Once the water heater is empty, leave the plug out or put it back in loosely.
Crucial tip: Turn the bypass valves on the back of the water heater now. You do not want to fill your 6-gallon or 10-gallon heater tank with 10 gallons of antifreeze. It's a waste of money and makes de-winterizing a nightmare.
Step 3: The blowout method (optional but recommended)
I like to use compressed air to get the bulk of the water out before I even touch the antifreeze. Screw your blowout plug into the city water inlet. Set your compressor to no more than 30-40 PSI. Anything higher can blow your plumbing apart, which defeats the whole purpose of what we're doing.
With the air running, go through the RV and open every faucet one by one—kitchen, bathroom, shower, and the toilet flush. Once you see nothing but a fine mist of air coming out, you're good. This ensures there are no big pockets of water left to dilute the antifreeze.
Step 4: Adding the RV antifreeze
Now it's time for the "pink stuff." There are two ways to get it into the lines. You can use a hand pump from the outside, or you can use your RV's internal water pump. Most people use the internal pump because it's easier.
- Find your water pump. There's usually a clear tube you can drop straight into the antifreeze jug. If not, you might need a "pump converter kit" which is just a simple T-valve.
- Turn on the water pump. It'll prime itself and start pulling the pink liquid into the lines.
- Start at the faucet closest to the pump. Open the cold side until you see bright pink liquid, then do the hot side.
- Move to the next faucet and repeat. Don't forget the toilet! Flush it until the water in the bowl turns pink.
- Check the outside shower and the city water inlet. (Pro tip: Be careful with the city water inlet; if you push the little check valve while it's under pressure, you might get a face full of pink slush).
Step 5: Don't forget the P-traps
Even if your lines are full of antifreeze, there's still water sitting in the P-traps under your sinks and in the shower drain. Pour about a cup or two of RV antifreeze down every drain. This replaces the water in the trap and prevents it from freezing and cracking the plastic pipe. Also, leave a little bit of antifreeze sitting in the toilet bowl. This keeps the rubber seal lubricated and prevents it from drying out and cracking during the dry winter months.
Finishing touches and a few warnings
If you have a residential refrigerator with an ice maker or a washing machine, the process is a bit more complicated. You'll usually need to run the ice maker cycle until it produces pink ice (or just clear out the lines thoroughly with air). These components are very fragile and very expensive to fix, so if you're unsure, check your specific appliance manual.
One last thing: disconnect your batteries. Even if everything is off, there are "phantom loads" (like the CO2 detector or the clock on the microwave) that will drain your battery to zero over a couple of months. A dead battery can freeze and crack, too. Either pull them out and put them in the garage or use a battery disconnect switch.
It feels like a lot of work the first time you do it, but once you get the rhythm down, you can winterize an entire travel trailer in about 20 or 30 minutes. It's a small price to pay for the peace of mind that comes with knowing your RV is safe. When those first warm days of spring roll around, you'll be able to just flush the lines, fill the tank, and head out to the campground while everyone else is stuck in the repair shop.
So, grab your wrench and a few jugs of pink stuff, and get it done before that first frost hits. Your future self will definitely thank you.