How to Drain Pipes for Winter: Stop Burst-Pipe Disasters Before They Start

A single frozen pipe burst in a winterized cabin can flood a basement with 8,000 gallons of water before the homeowner notices. Knowing how to drain pipes for winter is one of the highest-value DIY skills any homeowner with a vacation home, an unheated workshop, or a snowbird schedule can learn. Over the past two decades I have winterized hundreds of properties across northern climates, and the houses that get the procedure right never see a burst pipe, while the ones that skip a step always do. This guide walks you through exactly what works.

Why Pipes Burst in the First Place

Water expands roughly 9 percent in volume when it freezes. Inside a closed pipe with no room to grow, that expansion generates pressures up to 40,000 psi, far beyond what copper, PEX, or PVC can hold. The pipe splits, usually along a longitudinal seam, then leaks heavily when the ice thaws and water resumes flowing.

Pipes do not burst from cold alone — they burst because trapped water has nowhere to go. Drain the water and the cold becomes harmless. The entire winterization procedure exists to remove every drop from supply lines, drains, and fixtures so freezing temperatures do no damage.

Step 1: Shut Off the Main Water Supply

Start at the main shutoff valve. In most homes this is a ball valve near the water meter or where the supply line enters the house — usually the basement, crawlspace, or utility closet. Turn it 90 degrees so the handle is perpendicular to the pipe. For older homes with gate valves, turn the wheel clockwise until snug, then back off a quarter turn to protect the rubber washer.

If your home runs on a well, switch off the well pump breaker at the electrical panel. Drain the pressure tank by opening its drain valve into a bucket. Confirm no water comes from any fixture before moving on — a working main shutoff is non-negotiable.

Step 2: Open Every Fixture Top to Bottom

Start at the highest fixture in the house — usually an upstairs bathroom — and open both hot and cold sides of every faucet. Gravity pulls water down through the lines so air can replace it. Work top to bottom: upstairs sinks, downstairs sinks, tubs, showers, washing machine taps, outdoor hose bibs, basement utility sink.

Flush every toilet to empty the tank. Hold the lever down until the tank stops refilling. Open the toilet supply valve to drain the line behind it. Skip nothing — a single closed fixture traps water that will freeze and burst the supply line behind it.

Step 3: Drain the Water Heater Properly

The water heater holds 40-80 gallons that must come out completely. Shut off the gas valve or flip the breaker for an electric model. Hook a garden hose to the drain valve at the bottom of the tank and run it to a basement floor drain or outside if grade allows.

Open the drain valve, then open the pressure relief valve at the top to break the vacuum and let water flow freely. A full 50-gallon tank takes 20-30 minutes to drain. Leave both valves open through the winter. Mark the breaker so you do not energize the elements while the tank is empty — they will burn out in seconds.

Step 4: Blow Out Lines With Compressed Air

Gravity alone leaves pockets of water in horizontal runs and dishwasher loops. Use a compressor to push out the rest. The compressor only needs to deliver 30-40 psi — never exceed 50 psi on PEX or 80 psi on copper, or you risk damaging fittings.

Connect the compressor to an exterior hose bib using a male-to-male hose adapter and a blow-out plug. With the main shutoff still closed, slowly open the compressor air supply. Air will push water out through every open fixture. Work through them one at a time, closing each as soon as only air comes out.

Step 5: Add Antifreeze to Drain Traps

P-traps under sinks, shower drains, toilet bowls, and floor drains hold standing water by design. That water will freeze and crack porcelain or PVC if you do not address it. Pour non-toxic RV antifreeze into every drain — the pink Camco or Splash brand at any hardware store, never automotive antifreeze.

Use these quantities by fixture:

• Each sink trap — 1 cup of antifreeze poured slowly down the drain
• Toilet bowl — 2 cups in the bowl and 1 cup in the tank
• Tub and shower drain — 1 to 2 cups
• Washing machine drain — 1 cup down the standpipe
• Floor drains — 1 cup each
• Dishwasher — 1 cup poured into the bottom basin after draining the supply

Antifreeze keeps trap water from freezing solid. Without it, you risk cracking the trap and dealing with sewer gas leaks in spring.

Step 6: Handle the Toilet Reservoirs

Even after flushing, toilets retain water in the tank, bowl, and the rim jets along the underside. Sponge out remaining water from the tank. Bail the bowl down to the trap weir with a small cup. Pour antifreeze into both the tank and bowl as listed above.

The wax ring on the toilet flange holds water in some installations — there is no good way to drain it, but in practice it rarely freezes solid enough to damage the bowl. Some pros remove the toilet entirely on extended winterizations of remote cabins, then store it on a tarp until spring.

Step 7: Handle Outdoor Hose Bibs and Sprinklers

Frost-free hose bibs still need draining if a hose was left attached over winter. Disconnect every hose. Remove backflow preventers and rubber washers — they can crack at 28°F. Open and drain any vacuum breakers on irrigation systems.

If you have an in-ground sprinkler system, call a pro to blow out the lines with a 200 CFM compressor unless you own the equipment. Underpowered home compressors will not clear the lines, and trapped water in a single zone valve cracks a $400 part each spring.

Spring Re-Pressurization Done Safely

Reverse the order carefully in spring. Close every fixture and toilet supply valve. Open the main shutoff slowly to repressurize the system over 2-3 minutes. Refill the water heater completely before energizing it — a dry-fired element burns out in under a minute. Open each fixture and run until air sputtering stops.

Walk through the house and check every fitting, P-trap, and supply line for leaks. Listen for the sound of running water with all fixtures closed — that usually means a hidden burst somewhere. Done right, learning how to drain pipes for winter saves thousands in repair bills and gives you peace of mind every time the temperature drops below freezing.