How to Drain a Water Heater

Water heaters are one of the most used appliances in our homes. They aid us when we take a shower or a bath, when we do our laundry, when we clean our dishes and especially when we wash our hands. As with any other appliance, over time and with use, water heaters start to face certain problems.

Minerals that naturally occur in the water (hard water), along with sand and grit, settle in the bottom of the tank. Sediment buildup can reduce your water heater’s efficiency as well as erode the metal water heater itself. Buildup can also clog the tank drain, causing potential maintenance issues down the road that can ultimately lead your water heater to fail.

Because we rely on our water heaters so much, there are steps we can take to assure that they aren’t neglected on our list of home improvement to-dos. Learning how to drain a water heater is a fairly simple, DIY process that any homeowner can accomplish (if you come across anything that is not included in this article, do NOT move forward. Seek the help of a licensed plumber).

By draining your water heater once a year, you will ensure that it is working as efficiently as possible, you will increase its lifespan, and your water will be cleaner, all saving you money in the long run.

Please keep in mind that this service should NOT be performed on any water heater that hasn’t been flushed within the past three years. If your unit has been flushed in the past three years, you’re ready to proceed and learn how to drain a water heater.

1. Turn off the recirculation pump (if you have one): If you have an optional recirculation pump, unplug it from its power source. If not, move onto the next step.
2. Turn off the heat source: If you have a gas water heater, turn the burner control knob to the “pilot” setting. If you have an electric water heater, simply shut off the power by unplugging the system or turning it off in your electrical panel/circuit breaker.
3. Shut off the water supply: Most water heaters have a valve on the cold water line that is connected to the top of the water heater tank. If this is the case with your system, turn off the cold water supply valve here. If you don’t have this option, locate your home’s main water line and shut down the cold water from there.
4. Connect your hose to the drain valve: screw your hose (a garden hose will suffice) onto the water heater drain valve at the bottom of the tank, and lead your hose to the selected drainage area. You can drain the dirty water into your driveway, a floor drain, or anywhere that leads to the sewer or the street.
   If you don’t have any of these options, a bucket will work as well. By using a bucket, you can also monitor the extent of the corrosion that has taken place inside of your tank by the color of the draining water and the amount of sediment that flows out.
5. Open the drain valve: now that the hose is connected to the water heater, you can open the drain valve to release the tank’s water. You may be able to do this by hand, but sometimes a screwdriver is needed to assist in the process. The water will be hot, so use caution.
6. Let air into the tank: at this point, water will be draining from your hot water tank very slowly, if at all, due to the vacuum that exists inside of the tank. There are a couple of ways to let air in to break up the vacuum and get the water flowing:
   
   1. If your unit has a pressure relief valve that is connected to the tank, you can pop the valve to introduce needed air.
   2. If your pressure relief valve does not vent, you can also let air into the system by loosening the piping that connects to one of the water lines at the top of the water heater.
   3. Finally, a simple option to alleviate pressure from the system is to turn on the hot water tap on the faucet that is closest to your water heater.
7. Allow the tank to fully drain: Again, make sure to be cautious of the exiting hot water. Let all of the water completely drain from the tank. This can take anywhere from about 5-10 minutes, depending on the size of the tank.
8. Flush the tank: If you loosened any piping at the top of the water heater to let air into the system, make sure you tighten it back up. Then, turn the water back on by re-opening the water heater valve that we shut off in step 4. You can even smack the outside of the tank with your hand (be careful!) to try and break up any remaining sediment.
   Monitor the color of the water coming out of your hose, and allow the water to run for as long as it takes for it to come out clean and clear. A good rule of thumb is to let the water run for about 5-7 minutes regardless to be absolutely sure that your water heater tank is as clean as possible.
9. Close the drain valve and disconnect the hose: Re-close the drain valve using your hands or a screwdriver. Make sure that the valve, along with everything you disconnect and reconnect during this process, is fully tightened to avoid problematic leaks. Once the drain valve is securely closed, you can then disconnect the hose.
10. Turn on your hot water heater taps: Next, you’ll need to head inside and turn on every hot water tap on the faucets in your home to release any air that entered the water lines while draining the tank. Leave the hot water on for about 4-5 minutes or until all of the air is released from the water lines. You will be able to tell when this is accomplished as soon as the water starts running with normal pressure and without any spurting or pausing.
11. Turn the recirculation pump back on: If you have a recirculation pump that you unplugged at the beginning of the process, now is the time to plug it back in.
12. Turn the heat source back on: Finally, you can turn the burner for your gas water heater back on, or you can plug your electrical system back in or turn it on via the electrical panel/circuit breaker.

That’s it, you’re done! You can now go on to enjoy clean water with the comfort of knowing that your water heater is running at its best. For a step-by-step, visual guide on how to drain your water heater, check out this video that we love from CRC Plumbing: