RV Winterizing Without Antifreeze
Antifreeze is messy, costly, and a chore to flush each spring. Here's why air works better for RV water lines, and the kit that makes it a 15-minute job.
Every fall, the same debate pops up in RV groups: antifreeze or air? I live in Michigan, where winter temps drop well below zero. For the first two years, I bought RV antifreeze by the gallon, pumped it through the lines, and flushed it out every spring. In year three, I switched to air blowing and never looked back.
It’s not that antifreeze is a bad method. It has its place. But if you’re tired of that lingering aftertaste in your water lines every spring, air blowing might be the better fit. And the one small tool that makes it work well is a brass winterizing adapter with a built-in shut-off valve.
Antifreeze vs. Air Blowing: What’s the Difference?
These two methods work on different principles.
Antifreeze means pumping RV-specific propylene glycol through the lines to replace the water. The antifreeze itself will freeze, but it turns to a slushy consistency instead of expanding, so it won’t crack your pipes. Many RV manufacturers recommend this method because it’s more forgiving.
Air blowing uses compressed air to push the water out of the lines. No chemicals, no liquid left behind. The system stays dry.
Both have drawbacks.
With antifreeze, you have to buy it, pump it in, and flush it out in the spring. A gallon runs five or six dollars, and a mid-size RV usually needs three or four gallons. The bigger annoyance is the residue. Even after a thorough flush, that slightly bitter taste shows up the first time you use the water.
The risk with air blowing is that water can pool in low spots. If you don’t blow it out completely, that leftover water can freeze and crack a fitting. So the key isn’t whether you use air—it’s whether you blow it out thoroughly enough.
My approach: air blowing as the main method, with a little antifreeze at critical points. I blow out the lines with air, then pour a cup of antifreeze down each P-trap and the black tank valve. That way there’s no residue in the fresh water lines, and the low spots are still protected.
| RV antifreeze | Air blowing | |
|---|---|---|
| What it does | Replaces water with propylene glycol | Pushes water out with compressed air |
| Cost per season | $15–25 (3–4 gallons) | $0 if you already own a compressor |
| Spring cleanup | Flush every line | Nothing to flush |
| Residue | Possible bitter taste | None |
| Main risk | Missing a line or a P-trap | Water pooling in low spots |
| Typical time | 1–2 hours | 15–30 minutes |
Why the Tool Matters More Than the Method
Most discussions about air blowing focus on the PSI. 30 to 40 PSI is the accepted safe range. But hardly anyone mentions that the adapter you use to get air into the lines directly affects how clean and how easy the job is.
The most common winterizing adapter is a short brass piece—one end connects to an air compressor quick-connect, the other threads into the city water inlet. It’s cheap and it works. But it has two problems.
First, you’re constantly walking back and forth between the compressor and the RV. You have to open one faucet at a time, and every time you switch faucets, you walk back to the compressor to shut off the air. If you have eight outlets to blow out, that’s a dozen trips.
Second, it gets slippery in the cold. A bare brass fitting with wet hands in cold weather is hard to grip and hard to tighten.
The Saranice RV Winterizing Kit solves both issues.
Its 12.8-inch braided hose has a nylon cover, so it’s easy to grip even with wet or gloved hands. The hose itself is abrasion-resistant, so you can drag it around the driveway without worrying about damage.
More importantly, it has a built-in shut-off valve. You can turn the air on and off right at the adapter, without walking back to the compressor. Blow out the kitchen faucet, walk over and close the valve, move to the bathroom faucet, open the valve, keep going. No need to touch the compressor at all.
That difference sounds small, but after blowing out eight or ten outlets, you notice the saved steps and time. And it’s made with a brass body, 3/4" GHT threads, and a 1/4" industrial quick-connect, so it fits most home compressors and RV water inlets.
Step-by-Step: How to Blow Out Your RV Lines
If you decide to go with air, here’s the process.
Step 1: Drain the system. Turn off the water pump, disconnect from city water, and open all hot and cold faucets to release pressure. Open the low-point drain valves and the fresh water tank drain to let gravity do most of the work first.
Step 2: Deal with the water heater. Turn off the electric and gas to the water heater, let it cool, and pull the drain plug to empty the tank. If you’re only doing air and not antifreeze, leave the water heater bypass valve in the normal flow position—you don’t need to bypass it.
Step 3: Connect the winterizing adapter. Set your compressor to 30–40 PSI. Connect the air hose to the quick-connect on the adapter, and thread the other end into the city water inlet.
Step 4: Blow out one faucet at a time. Open the air valve, then open one faucet. Kitchen, bathroom, shower, outdoor shower, toilet—blow each one until only air comes out. Close that faucet, move to the next, and repeat. This ensures the air pushes water ahead of it instead of escaping through all open faucets at once.
Step 5: Don’t forget low-point drains and the toilet. Blow out the low-point drain valves too. For the toilet, step on the flush valve to let air pass through.
Step 6: Finish up. Close the air valve, remove the adapter, and put the city water inlet cap back on to keep bugs out. Pour a cup of RV antifreeze down each P-trap to prevent sewer odors from backing up.
More Than Just RV: Other Uses for This Kit
The female end of the Saranice kit is standard 3/4" GHT garden hose thread, which means it’s not just for RVs. Sprinkler systems, irrigation lines, garden hoses, boat fresh water systems—anything with a 3/4" GHT connection can be blown out with this adapter.
After I blow out the RV lines in the fall, I use the same kit on my backyard sprinkler zones. One tool, two uses. No need to buy a separate sprinkler blow-out adapter.
One thing worth knowing: if your spigot sits low to the ground or tucked behind siding, a 45° garden hose elbow or a 90° elbow keeps the hose from binding against the wall when you hook the kit up.
Frequently Asked Questions
Q: Can air blowing completely replace antifreeze?
A: It depends on your climate and how complex your RV plumbing is. If your lines are simple and your winters aren’t extreme, blowing them out thoroughly is usually enough. For complex systems or extreme cold, use air first, then add antifreeze at the low points.
Q: What PSI should I use?
A: 30 to 40 PSI is the safe range. Don’t exceed 60 PSI, or you risk damaging PEX tubing or fittings.
Q: Does the winterizing adapter need Teflon tape?
A: No. The kit comes with a rubber gasket, and hand-tightening is enough to seal.
Q: Do I need to keep the compressor running the whole time?
A: No. Use the shut-off valve on the adapter. Open it for the faucet you’re blowing out, close it when you’re done, then move to the next one.
Q: Can this kit be used on a sprinkler system?
A: Yes. The female end is 3/4" GHT, so it threads directly onto most sprinkler zone connections. Use the same air blowing process.
If You’re Tired of Pumping Antifreeze Every Fall
Air blowing isn’t the only method, but it’s the cleanest one. No chemical residue, no bitter taste in the spring, no hauling gallons of liquid around every year.
And a winterizing adapter with a shut-off valve and a grippy braided hose turns the whole job from “an afternoon crawling under the RV” into “done in half an hour.” The Saranice RV Winterizing Kit has a brass body, nylon-braided hose, and a built-in valve—you can find it here.
If you want to try air blowing this year, this is the tool that makes it a lot easier.