Winterize a Cabin Water System Before It Freezes

To winterize a cabin water system, shut off the water supply and the power to the pump and water heater. Then drain every line and fixture from the lowest point, and pour RV antifreeze into the drain traps and toilets. On most small cabins this takes one afternoon, and it costs far less than one split pipe in a crawlspace.

Updated September 25, 2026. Now is the time to plan it, because the high country can get a hard freeze before the leaves finish turning. If you’ll be up for one last fall weekend anyway, do the job before you head home.

When should you winterize a cabin water system?

Winterize before the first hard freeze, which usually means at least a few hours at 28 degrees or colder. A light frost on the truck windshield won’t split a pipe. A long, cold night in an unheated crawlspace can.

In West Virginia, elevation sets the timing more than the calendar does. A cabin in Tucker, Randolph, or Pocahontas County above 3,000 feet can freeze weeks before a place along the Ohio River, and Canaan Valley has a reputation for frost in nearly any month. My guide on first frost dates across West Virginia breaks this down by region.

A good rule is to do it on your last visit of the season, even if that falls in late September. Many people plan one more trip up for peak fall color at higher elevations and then end up not making it. Don’t bet the plumbing on that trip.

What do you need to winterize cabin plumbing?

You need a garden hose, a bucket, a few jugs of RV antifreeze, and a large sponge. An air compressor with a hose-bib adapter helps a lot but isn’t required. A flashlight and knee pads make the crawlspace part less miserable.

Before you start, find every drain valve. Look at the low point of the main line, the bottom of the water heater, the bottom of the pressure tank, and any filter housings. If you don’t know where the lowest point in the system is, find out now, because that’s where the water collects and freezes.

If you’re short on a fitting or a roll of foam pipe insulation, check the Cozy In WV deals page before you make the drive. Hardware stores near the remote cabin areas close early in the off-season.

How do you drain a cabin water system step by step?

Cut the power and water first, open everything up high, then drain from the lowest point. Water needs air coming in above it to drain out below, the same way a straw holds liquid when you cap the top. Here’s the order that works for most cabins.

1. Turn off the breaker for the well pump and the water heater. On a gas water heater, set the gas valve to off or pilot according to the label on the tank.
2. Close the main shutoff valve. On city or public water, you can also ask the water utility to shut the curb stop.
3. Open every faucet in the cabin, hot and cold, starting with the ones on the highest floor.
4. Open the drain valve at the lowest point of the system and let it run until it stops.
5. Flush each toilet and hold the handle down to empty as much of the tank as possible.
6. Open outdoor spigots and disconnect garden hoses. Leave frost-free hydrants open so they drain.
7. Disconnect the washing machine hoses and drain them. Shut off the ice maker line and the dishwasher supply.
8. Remove filter cartridges and drain the filter housings. Do the same for a water softener or UV unit according to its manual.

Leave the faucets open when you’re finished. Any water left in a low spot then has room to expand without building pressure. Tape a note to the main valve that says the system is winterized, so nobody turns it on in January with the drains open.

How do you drain the water heater safely?

Turn off the power or gas first, let the water cool, then drain it through a hose from the valve at the bottom. An electric heater that gets power while it’s empty will burn out its heating elements in minutes. That’s the most common and most expensive mistake people make with this job.

Give the tank a few hours to cool if you can, because water straight out of a heater can scald. Run the hose outside to a spot downhill from the cabin or to a floor drain. Open a hot water faucet somewhere in the cabin so air can get into the tank, or it will barely drain.

Older tanks collect sediment, and it can clog the drain valve partway through. Opening and closing the cold inlet for a few seconds usually stirs it loose. A tankless heater has its own drain plugs and is easier to damage by freezing than a tank, so follow its manual.

Do you need to blow out the lines with air?

Blowing out the lines is the best way to get the last water out, and I’d do it on any cabin that sits empty all winter. Gravity draining leaves water sitting in every sag and low run of pipe. Those small pockets are enough to crack a fitting.

Connect the compressor to a hose bib or the main drain with an adapter, and keep the pressure low. Many plumbers use somewhere around 40 to 50 psi on residential lines. Open one faucet at a time, hot and cold, until only mist comes out, then close it and move to the next.

PEX tolerates a freeze better than copper does, but the brass fittings and valves on a PEX system can still split. Don’t skip this step because the cabin has plastic pipe.

Where does RV antifreeze go?

RV antifreeze goes into every drain trap, every toilet bowl, and any appliance whose manual asks for it. The traps under sinks, tubs, and showers hold water by design, and draining the supply lines won’t empty them. A cup or two in each trap stops the freeze and keeps the sewer gas seal.

Use only the pink antifreeze labeled for RV or marine plumbing, which is propylene glycol. Car antifreeze is ethylene glycol, and it’s toxic to people, pets, and wildlife. In small amounts, propylene glycol is generally considered fine for a septic system, but car antifreeze is not.

For toilets, sponge the last water out of the tank, then pour antifreeze into the bowl until the trap is full. Don’t forget the washing machine standpipe, a floor drain in the basement, or the drain in a utility sink. People miss these most often.

What about a well pump, spring line, or cistern?

For a well, kill the pump breaker and drain the pressure tank from the valve at its base. A submersible pump sits deep in the casing below the frost line, so the pump itself is usually safe. The pressure tank, the pressure switch, and any pipe in an unheated pump house are the parts that freeze.

A jet pump in a well house has a drain plug on the pump casing. Take it out and store it somewhere you’ll find it in April. The small tube that feeds the pressure switch can also hold water, so blow it out if you can reach it.

Lots of older mountain cabins run on a spring box or a cistern with a gravity line. Lines buried below the frost line usually do fine, and freezes tend to happen where the pipe comes up out of the ground into the crawlspace. Open that section at its lowest point, drain any pump off the cistern, and wrap exposed pipe where it enters the cabin.

Can you leave the heat on instead of draining?

You can, but only if you keep the thermostat at 55 degrees or higher and have a way to know when the heat fails. The danger at a remote cabin is a power outage during an ice storm while you’re two hours away. Propane can also run out without anyone noticing.

A wood stove can carry a cabin through the night, as I cover in keeping a wood stove burning overnight, but it won’t hold heat for a week while you’re home in Charleston. For a cabin left empty, a low-temperature alarm that sends a text is worth having. So is a neighbor down the road who’s willing to check on it.

If you go this route, open the cabinet doors under sinks on exterior walls and put foam insulation on exposed pipe in the crawlspace. Heat tape works on problem runs, but it has to be listed for the pipe material and installed exactly as the instructions say. Honestly, for a cabin you won’t visit until spring, draining is the safer bet.

How do you turn the water back on in spring?

Close all the drain valves, put the plugs back in, and fill the water heater completely before you turn its power on. Open a hot faucet and wait until it runs in a steady stream with no sputtering air. Only then is the tank full enough to turn on the breaker.

Open the main valve slowly, because a sudden rush of pressure is hard on fittings that have sat all winter. Run each faucet until the antifreeze clears from the traps, and flush the toilets a couple of times. Then check under every sink and in the crawlspace for drips, since a small crack from a missed pocket of water shows up now.

While you’re opening the place up, look over the stove pipe too. My post on how often to clean a wood stove chimney explains what to look for before the first fire of the next season.

Frequently asked questions

If you only remember one thing, remember the water heater: turn off the power before you drain it and fill it before you turn the power back on. Everything else comes down to getting the water out of the pipes before the cold gets in.

Pick a dry afternoon on your last trip up, take your time in the crawlspace, and write down where every drain valve is. Next fall, that list will turn this into an hour’s work.