Do You Leave Faucets Open When Winterizing RV
Leave faucets open only if you're blowing out the lines with compressed air. If you're using antifreeze, you open them to bleed air and close them once antifreeze flows through.
It depends on which winterizing method you're using
If you're blowing the water lines out with an air compressor, you leave the faucets open while you do it. The open faucet is how you know the water has cleared that line. Once air blows through steady and no more water comes out, you move to the next faucet.
If you're using RV antifreeze instead, the faucets stay open only briefly. You open each one, let the pink antifreeze run through until you see it coming out the tap, then close it. Leaving them open after that just wastes antifreeze and won't protect anything further.
Which method you're using changes everything about the faucets
Compressed air and antifreeze are two different ways to protect the same lines, and they call for opposite habits. With air, the faucet has to stay open the whole time you're pushing air through that line, because the open faucet is what lets the water and air escape. Close it too soon and water stays trapped behind it, right where it can freeze and crack a fitting.
With antifreeze, the goal is different. You're trying to get antifreeze into every line, not air. You open the faucet, run the pump or gravity-feed the antifreeze through, and close the faucet as soon as the antifreeze shows up at the tap. Leaving it open after that just drains antifreeze out of the system instead of keeping it in the lines.
Some owners use both methods together, blowing out the bulk of the water with air first, then running a small amount of antifreeze through for extra protection. If you're doing that, the faucet sequence matters even more. Blow the line out with the faucet open, then close it before you switch to antifreeze, so the antifreeze stays in the line instead of blowing straight through.
If you're not sure which method your RV's plumbing calls for, check the owner's manual. Some RVs have low point drains that need to be open at a different stage than the faucets themselves, and the order you do things in matters as much as whether a given faucet is open or closed.
What people get wrong about leaving faucets open afterward
A common mistake is leaving faucets open once winterizing is done, thinking it protects the lines over the winter. It doesn't. Once the water is out and the antifreeze is in, the faucets should be closed. An open faucet left all winter just lets air and moisture into the line, and it doesn't do anything to prevent freezing on its own.
Another thing people miss is forgetting the outdoor shower, the toilet sprayer, and the ice maker line if the RV has one. These faucets need the same open-then-closed treatment as the kitchen and bathroom sinks. Skipping one of them is one of the most common reasons a line freezes and cracks even after the main winterizing job is done.
It also matters whether the water heater bypass valve is set correctly before you start. If it isn't, antifreeze runs into the water heater tank and never reaches the faucets the way it should, so you can leave a faucet open and still not see antifreeze come through because the line ahead of it is blocked or misrouted.
Questions people ask about this
How do I know when to stop running antifreeze through a faucet?
Stop once the antifreeze itself, not water, comes out the tap in its full color. Running it longer than that just uses more antifreeze without adding protection. Check both the hot and cold side of each faucet separately, since they're often fed by different lines.
Do I need to winterize the outdoor shower and toilet sprayer too?
Yes, any faucet or sprayer connected to the water system needs the same treatment as the sinks. These are often mounted outside or tucked in a wet bay, so it's easy to forget them. Check your RV's plumbing diagram if you're not sure how many fixtures are on the system.
What happens if I forget to close a faucet after winterizing?
A faucet left open all winter won't by itself cause damage, but it's a sign the line wasn't protected properly in the first place. If it was supposed to have antifreeze in it and doesn't, that section of line is still exposed to freezing temperatures. Walk through each faucet again to confirm antifreeze actually made it through.
Do I need to winterize the water heater separately from the faucets?
Yes, the water heater needs its own step, usually bypassing it so antifreeze doesn't fill the tank unnecessarily. If the bypass valve isn't set before you start on the faucets, antifreeze can get diverted into the tank instead of reaching the lines. Check your RV's manual for where the bypass valve is and how to set it.
Can I winterize my RV using only compressed air and no antifreeze?
Yes, some owners rely only on compressed air to blow all water out of the lines, skipping antifreeze entirely. This works if every line is fully cleared and low point drains are opened too, since trapped water in a low spot can still freeze. If you choose this method, go slowly and check each faucet and drain so no pocket of water gets missed.
Getting your RV ready for winter is a good reason to see what else you could be paying for insurance.
Finish winterizing one water system at a time rather than jumping between methods, so you don't lose track of which faucets are open or closed. Keep your RV's owner's manual nearby for the bypass valve location and the low point drain positions, since missing either one can undo the rest of the work. If anything about your plumbing layout is unclear, a quick call to the manufacturer or a dealer's service department can save you from guessing. Once the RV is winterized, it's also a good time to check that your RV insurance reflects how the vehicle is stored and used over winter, since coverage needs can shift between full-time and seasonal use.
