How to Drain a Water Heater

By
Aaron Stickley
Aaron Stickley

Aaron Stickley is a licensed plumber with 15 years of experience in commercial, new residential plumbing, and residential service and repair. He started his own residential service and repair plumbing business. Aaron's articles about plumbing on The Spruce span four years.

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Updated on 05/03/22
Reviewed by
Richard Epstein
Richard Epstein
Reviewed by Richard Epstein
Richard Epstein is a licensed master plumber with over 40 years experience in residential and commercial plumbing. He specializes in estimating as well as design and engineering for plumbing systems, and he works for one of New York's largest union plumbing construction companies.
Learn more about The Spruce's Review Board
Yellow garden hose and screwdriver for draining water heater

The Spruce / Kevin Norris

Project Overview
  • Working Time: 1 - 2 hrs
  • Total Time: 1 - 2 hrs
  • Skill Level: Beginner
  • Estimated Cost: $0

Most water heater maintenance manuals suggest that you drain a water heater at intervals ranging from six to 12 months. The reason this is recommended is to help remove any sediment or buildup that collects on the bottom of the water heater tank due to minerals and other particles in the water. This buildup will cause the water heater to work harder to heat the water, using more energy and costing more money to run.

Before You Begin

Before getting started, make sure you know where your home's main water shutoff valve is located. While you won't necessarily need it during this process, it's always a good idea when working with any kind of plumbing fixtures in your home to be acquainted with this valve in case something goes wrong and you need to stop all water flowing through your pipes.

Safety Considerations

This process involves working with water that can be extremely hot. You might want to turn off your hot water heater several hours before you begin in order to let the water in the tank cool off. If you're not able to do that, then use heavy-duty rubber work gloves to protect your hands from any splashes and use safety glasses to keep your eyes safe from hot water droplets.

What You'll Need

Equipment / Tools

  • Adjustable wrench
  • Garden hose
  • Flat-head screwdriver
  • Bucket

Materials

  • Drain valve (if necessary)
  • Threaded hose cap (if necessary)

Instructions

Materials and tools to drain a water heater

The Spruce / Kevin Norris

  1. Perform a Quick Flush

    Before you shut off the water, connect a garden hose to the drain valve and try and flush the water heater tank a bit while the water pressure is on. To do this, open the drain valve for a few seconds and then close it again. The pressure will blow out any sediment stuck in the valve and help the tank drain faster. If quite a bit of sediment comes out, you can repeat this a couple of times.

    Be sure that you've run your garden hose to either an exterior location or into your bucket to catch the water and sediment that will be released.

    Garden hose connected to drain valve on water heater

    The Spruce / Kevin Norris

  2. Turn Off the Water Heater

    Shut off the gas to your water heater, or shut off the power if it is an electric heater. Now shut off the water, using either the valve in the cold-water pipe above the water heater or the main water supply valve to the house. Make sure the pressure is off by testing the hot water faucets in the house, turning them on, and checking for water. Water may gush out at first, but should quickly slow to a trickle if the water has been shut off properly. Be sure to leave a hot water tap open in the sink nearest to your hot water heater to alleviate pressure in the system.

    Cold water pipe turned off with shutoff valve

    The Spruce / Kevin Norris

  3. Open the Drain Valve

    With your garden hose attached, open up the drain valve. You can usually do this by hand, but you might need to use your flat-head screwdriver here.

    Once the valve is open, water will begin to gush out of the drain so again, be sure your hose either leads outside or into your bucket. As the bucket fills, turn off the drain valve so that you can dump it. Repeat the process until the water runs clear.

    Drain valve opened with flat-head screwdriver on water heater

    The Spruce / Kevin Norris

  4. Clean the Sediment

    You can take a few buckets of water out of the tank to remove any sediment that accumulates at the bottom of the tank. When the outflow runs clear, you'll know that you've removed the sediment and you can move on to the next step.

    Shutoff valve turned on to flush water heater tank

    The Spruce / Kevin Norris

  5. Turn on the Water Heater

    Shut off the drain valve and disconnect the garden hose. Be sure all but one of the hot water taps in your home are closed (the one in the bathtub closest to the water heater is best).

    Now you can turn the water back on to the water heater. Re-energize the system slowly by partially opening the valve. Once the system is fully energized, open the valve to a fully open position. After doing so, monitor the tap you left open and, once you are getting nothing but water out of the fixture, turn it off.

    Water heater refilled with garden hose attached

    The Spruce / Kevin Norris

  6. Relight the Water Heater

    Relight the water heater pilot, or turn the power back on if it is an electric heater. Within an hour or so, you should have hot water.

    Power switch turned on to relight water heater

    The Spruce / Kevin Norris

  7. Check the Drain Valve

    See if your water heater drain closed completely by looking for leaks at the spout. If it did not close completely, you can put a threaded hose cap over the hose thread of the outlet to stop the leak. Or, you can replace ​the valve completely.

    Water heater drain valve checked for leaks

    The Spruce / Kevin Norris