How To Winterize a Toilet

toilet bowl with blue water
What You'll Need
Non-toxic, plumbing grade antifreeze
Safety glasses
Old towels
Sponge or washcloth

If you have a bathroom that reaches freezing temperatures in the winter, you'll probably want to shut off the water there for the coldest months. Freezing in your toilet or its tank can result in substantial damage along with unwanted plumbing issues.

How Your Toilet Works

Your toilet has two main parts: the tank and the bowl. The bowl holds water and connects to the drain to allow you to get rid of water and waste. The tank sits behind the bowl, containing a reserve of water that flushes out the bowl as needed.

a toilet tank from the top down

Inside the tank is the fill valve, also referred to as the ballcock. It typically lives on the left side of the tank. This is the “gatekeeper” of water, responsible for allowing fresh water supply to refill the tank after the toilet is flushed, then closing to prevent too much water from entering.

Finally, the shut-off valve exists outside the toilet, near the wall towards the back of the toilet close to the ground. This is usually on the left side of the toilet under the tank. This can be turned to shut off water to the toilet completely. For that reason, this is an important toilet component for this project.

Step 1 - Ensure You’re Done Using It

Before you go through the steps of winterizing your toilet, make sure it definitely doesn’t need to be used any more until the winter is over. It would be pretty difficult to reverse these steps at a moment’s notice if nature calls.

Step 2 - Drain the Tank

Use the “fill valve” or “ballock” control—usually mounted on the left side of the tank—to help you drain the tank. Switch the valve to off so that water will stop flowing into the tank. Also flip the shut-off valve, which is located on the wall or floor near the toilet bowl.

Once the valves are switched, remove the top of the toilet tank and place it on the floor. This allows you to watch the water drainage of the tank in real time. Press the handle down to flush the toilet, holding it down until all the water has drained out of the tank. This pushes that water through your pipes. Continue holding the handle down until all water is drained. If that’s not happening, verify that the cut-off valve has been correctly switched.

emptying toilet bowl

Step 3 - Drain the Bowl

After your toilet’s tank is empty, there will likely be some water lingering in the bowl. This step of the process could get a bit messy, so in preparation for that, lay old towels on the floor around the bowl. Now, fill a bucket with three to five gallons of water. Raise the bucket above the toilet and begin pouring the water into the bowl. As you’re pouring, gradually lift the bucket higher and higher to change the momentum of water flow into the bowl.

The reason for doing this is that the momentum of water flowing from the bucket into the bowl will push almost all the water in the bowl into the drainage system. Once the water from the bucket is depleted and the bowl is virtually dry, use a sponge or washcloth to completely dry out the toilet bowl.

Step 4 - Add Antifreeze

The last step of this process is to add antifreeze. Do this carefully, and consider wearing safety glasses as this substance is dangerous if it gets into your eyes. The antifreeze should be non-toxic and marked as safe to use in plumbing systems. Pour it directly into the tank of your toilet. As you pour it in, hold down the lever to flush the toilet to force some of the liquid into the other parts of your system.

Winterizing your toilet is just the beginning of preparing your plumbing system for the winter months, particularly if you’re not going to be present for the duration of the season at your home. Make sure not just to turn off your water, but to drain all pipes that could be exposed to freezing cold.