How to Drain a Water Heater

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.

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.

• Total Time: 1 - 2 hrs

• Skill Level: Beginner
• Estimated Cost: $0

Draining the water heater is a regular maintenance task that only takes an hour and costs nothing if you own a garden hose and a few basic tools. This process removes sediment or buildup that collects on the bottom of the water heater tank. This buildup makes the water heater work harder, using more energy and costing more to run.

Learn how to drain your water heater to save energy and money and to increase the unit's lifespan.

Warning

Before draining your water heater, make sure you know what type you have, gas or electric. Follow all manufacturer instructions and recommendations carefully to avoid damage during drainage.

How Often to Drain a Water Heater

Drain the water heater once a year. Drain the heater twice a year for areas with hard water (water with a high mineral content) or older water heaters.

Before You Begin

Locate your home's main water shutoff valve in case something goes wrong and you need to quickly shut off all water. Turn off the water heater several hours before you plan to drain it. Wear heavy-duty rubber work gloves and safety glasses.

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

How to Drain a Water Heater

Turn Off the Power

Shut off the gas to your water heater or shut off the power if it is an electric heater.

• Gas water heater: A mid-line shut-off valve will be located on the gas pipe near the water heater. Turn the valve to shut it off.
• Electric water heater: Electric water heaters have a control panel that lets you shut them off. Or, more expediently, shut off the circuit breaker that controls the water heater.

Perform a Quick Flush

• Connect a garden hose to the drain valve.
• Run the end of the garden hose to an exterior location or into a bucket to catch the water and sediment that will be released.
• Flush the water heater tank briefly while the water pressure is on. Open the drain valve for a few seconds and then close it again.

Shut Off the Water Supply

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.

Open the Drain Valve

Open up the drain valve with your garden hose attached. You can do this by hand, but you may need to use your flat-head screwdriver. 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.

Clean the Sediment

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

Turn on the Water Heater

• Shut off the drain valve and disconnect the garden hose.
• Leave only one hot water tap open in your home (the one in the bathtub closest to the water heater is best).
• Re-energize the system slowly by partially opening the valve.
• Open the valve to a fully open position once the system is fully energized.
• Monitor the tap you left open. Turn it off once there's nothing but water coming out of the fixture.

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.

Check the Drain Valve

Look for leaks at the spout to see if your water heater drain is closed. If it did not close, put a threaded hose cap over the hose thread of the outlet or entirely replace the valve.

It is necessary to drain a water heater. If you live in an area with soft water (water with little mineral content), you may need to drain it only every two to three years.

You cannot drain your water heater without turning off the water. However, it is not necessary to turn off the main water supply to the entire house. You'll find an in-line water shut-off valve near the water heater.

After draining the water, a 50-gallon water heater takes 30 to 60 minutes to heat up, while an 80-gallon water heater takes close to two hours.