Learning how to winterize a water heater is one of those chores you really don't want to skip if you have a vacation cabin, a rental property, or even a home that's going to sit empty during the freezing months. It might seem like a bit of a project, but it's a whole lot better than coming back in the spring to find a flooded basement and a tank that's split wide open. When water freezes, it expands with incredible force, and a metal tank doesn't stand a chance against that kind of pressure.
If you're planning on leaving a building unheated while the temperature drops below freezing, you've got to get that water out. Let's walk through the process so you can check this off your list and enjoy your winter without worrying about your plumbing.
Why You Shouldn't Skip This Step
It's easy to think that if you just leave the heat on a low setting, everything will be fine. But what happens if the power goes out during a blizzard? If the furnace stops, the temperature inside can plummet fast. A water heater full of sixty gallons of water becomes a giant ice cube, and once that tank cracks, there's no fixing it—you're looking at a total replacement.
Beyond just the tank, there are the pipes connected to it. By learning how to winterize a water heater, you're also protecting the surrounding plumbing. It's all about peace of mind. You're basically putting your plumbing system into a "deep sleep" so it stays safe until you're ready to wake it up again.
Getting Your Tools Ready
You won't need a specialized degree in plumbing for this, but you will need a few basic things. Grab a standard garden hose—one that's long enough to reach a floor drain, a sump pump, or even out the front door. You might also want a flathead screwdriver and maybe a couple of old towels in case of small spills.
It's also a good idea to have some work gloves. The water coming out of the tank can be surprisingly hot if you haven't let it cool down first, and the metal valves can sometimes be a bit stubborn to turn.
Turning Off the Power or Gas
Before you touch a single drop of water, you have to deal with the energy source. This is the most important safety step.
If you have an electric water heater, go to your breaker box and flip the switch to "off." Don't just turn it down at the thermostat; you need the power completely disconnected. If the heating elements turn on while the tank is empty, they'll burn out in seconds. That's a mistake that's both annoying and expensive to fix.
If you're working with a gas water heater, you have a couple of choices. Most people just turn the dial on the bottom of the unit to "Pilot" or "Off." If you're going to be gone for months, turning it to "Off" is the safest bet. You should also close the main gas shut-off valve on the pipe leading into the heater just to be extra safe.
Shutting Off the Water Supply
Now that the power is handled, you need to stop more water from coming in. Look for the cold water pipe entering the top of the heater. There should be a valve there—usually a lever or a circular handle. Turn it until it's fully closed.
If that valve looks old or feels like it might snap, you can always turn off the main water supply to the whole house. Honestly, if the house is going to be empty, turning off the main water is a smart move anyway. It's the "belt and suspenders" approach to home maintenance.
Draining the Tank
This is where the garden hose comes in. Find the drain valve at the very bottom of the tank. It usually looks like a little plastic or brass faucet. Attach your hose to it and run the other end to a safe spot where sixty gallons of water won't cause a mess.
Before you open that valve, you need to break the vacuum inside the tank. If you don't, the water will just glug or might not come out at all. The easiest way to do this is to go upstairs and turn on the "hot" side of any faucet. You'll hear a little hiss as air enters the system, which allows the water to flow out the bottom of the heater freely.
Open the drain valve on the heater. This part takes a while, so feel free to go grab a coffee or tackle another chore while gravity does its thing.
Dealing with the Sediment
While you're figuring out how to winterize a water heater, you might notice the water coming out of the hose looks a bit "crunchy" or discolored. That's just sediment—minerals like calcium that settle at the bottom over time.
Draining the tank for winter is actually a great excuse to flush this stuff out. Once the tank is empty, you can briefly turn the cold water intake back on for a minute. This "stirs up" the bottom and flushes more of that gunk out through the hose. It helps your heater run more efficiently when you start it back up, so it's a nice little win-win.
What About Tankless Water Heaters?
If you don't have a big tank, you might think you're off the hook. Not quite! Tankless units still hold a small amount of water in their heat exchangers. Most modern tankless models have a "freeze protection" feature, but that only works if the power stays on.
To winterize a tankless unit, you'll need to turn off the power and gas, then drain the unit using the isolation valves (if you have them). You might even need to use an air compressor to gently blow out any remaining water from the internal copper piping. It's a bit more technical, but the core idea is the same: no water left behind.
Leaving the Valves Open or Closed?
Once the tank is totally empty, you'll want to close the drain valve at the bottom so you don't lose the washer or have bugs crawl in there. However, it's often a good idea to leave the faucets inside the house in the "open" position. This prevents pressure from building up in the lines if there's any tiny bit of moisture left that might freeze and expand.
How to Re-start the System in the Spring
When the snow melts and you're back at the house, don't just flip the power back on. If you turn on an electric heater before it's full of water, you'll fry the elements instantly.
- Close the drain valve at the bottom of the heater (if you left it cracked open).
- Turn on the main water supply and the intake valve to the heater.
- Keep the hot water faucets in the house open. You'll hear a lot of air sputtering and coughing out of the tap.
- Once a steady stream of water comes out of the faucets, you know the tank is full.
- Now you can turn the electricity or gas back on.
Final Thoughts
Knowing how to winterize a water heater is a solid skill that every homeowner should have in their back pocket. It's one of those tasks that takes about thirty minutes of active work but can save you thousands of dollars in potential water damage.
It might feel a bit tedious when you're busy packing up and trying to get on the road, but your future self will definitely thank you. Just remember: power off first, drain it completely, and don't forget to break the vacuum. Stay warm, and don't worry—your water heater will be waiting for you, safe and dry, when you get back!