How to Drain Your Hot Water Heater

Help your appliance last longer and work better with this totally-worth-it DIY

Conroy Baltimore
Written by Conroy Baltimore
Reviewed by Jeff Botelho
Updated May 20, 2022
Man Repairing Water Heater
Photo: Ramon Espelt / EyeEm / Getty Images
Difficulty

Easy

Simple project; big impact.

Time to complete

2 hours

1 to 2 hours total.

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What you'll need:

TOOLS

  • Adjustable wrench
  • Flathead screwdriver
  • Garden hose
  • Bucket

SUPPLIES

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

The hot water heater may well be the hardest working appliance in your home, and yet it’s also probably the appliance you think least about. That is until it stops working—almost inevitably in the middle of a nice warm shower or a hot laundry cycle.

But you shouldn’t wait for signs of trouble to show your home’s hot water heater some love. In fact, with a bit of routine maintenance, you can keep your water heater humming for years to come. One of the best ways to promote water heater health? Regular draining and flushing.

How to Drain and Flush a Water Heater

As important as it is to drain and flush your hot water heater, the good news is it’s a relatively quick and easy DIY task. Here’s how you do it:

  1. Familiarize Yourself with Your Water Heater

    Review your water heater owner’s manual and the instructions posted on the side of your tank. These will help you identify where all the necessary drains and valves are.

  2. Turn Off Power to Your Heater

    For electric water heaters, locate the heater’s circuit breaker in your home’s electrical panel and turn it off. Make sure you also turn off the thermostat on the water heater itself because heating an empty tank can damage it. For gas water heaters, you will need to turn the gas supply valve to the “Pilot” setting.

  3. Turn Off Water Supply to the Heater

    If your heater has a valve connected to its water supply line, just turn the water off from there. But if there is no valve, you’ll need to turn off the supply at your home’s water meter.

  4. Let the Water Cool Down

    Allow the water in the tank to cool down, or turn on the hot water faucets in your home to replace the hot water in your heater with cold water. Remember that the water can be very hot, so to avoid burns and scalds, you may want to wear protective goggles and gloves while working in the tank and drainage area. You’ll also want to keep children and pets clear of faucets and drains while you work.

  5. Release the Water Pressure

    If you haven’t already done so, turn on a hot water faucet in a sink or shower on the top floor of your home. This will release pressure in the line and ensure that a vacuum doesn’t form, which would prevent your system from draining and flushing completely.

  6. Attach a Garden Hose to the Drain Valve

    Locate the pressure relief valve near the top of your water heater and the drain valve near the bottom. Attach a garden hose to the closed drain valve and place the other end in a drain bucket, sink, or outside. The hose should be lower than the drain valve to ensure a strong water flow. Again, take care to keep children and pets away from the discharge area, as the water may still be hot.

    Note: If your water heater is located in your basement, you may need a transfer pump to remove water from the tank and up and out of your basement. These pumps can be pretty expensive to buy, but you can often rent them from home improvement stores for a wallet-friendly price.

  7. Open the Drain Valve to Flush

    Open the drain valve completely by turning it counterclockwise.

  8. Flush the Sediment

    When the water stops flowing from the hose, turn on the water supply valve at the top of the tank or at the water meter. This will flush any remaining sediment from the heater.

  9. Close the Drain Valve

    When the water from the hose runs clear and free of sediment, shut off the water supply valve and close the drain valve, checking to ensure the drain is completely closed and leak-free.

  10. Turn the Water Supply Back On

    Turn on the water supply line again and check the sink and shower faucets you had previously turned on. Ensure that the water from these faucets runs clear and free of sediment. If not, then repeat the drain and flush steps until the water from the taps is clear. Once the water from the faucets has regained normal pressure, shut off the faucets.

  11. Disconnect the Hose and Run Your Water Heater

    You’re now ready to disconnect your garden hose and get your water heater up and running again! For electric heaters, turn on the thermostat on the heater and the circuit breaker at the electrical panel. For gas water heaters, turn on the gas supply line. 

    Set your water heater’s thermostat to 140 degrees Fahrenheit to help maximize energy efficiency and deter bacterial growth. And that’s it! You’re all set for another year of warm baths and clean laundry

Why You Should Drain Your Hot Water Heater

Taking the time to drain and flush your hot water heater isn’t just about ensuring your hot water is clear and particle-free. It will also help prevent your heater and pipes from rusting internally. Routine draining and flushing help your water heater run more efficiently, producing significant savings in energy costs every year.

Not only that, but if you allow your water heater to collect mineral deposits, you’re likely going to lose water pressure and experience burst pipes. Over time, sedimentation and corrosion can severely damage your water heater. You can end up spending as much as $1,000 to replace your hot water heater far sooner than was necessary.

How Often Should You Drain and Flush Your Hot Water Heater?

How often you drain and flush your hot water heater depends on a number of factors, from the age of your water heater and pipes to the metals and other elements in your water supply. On average, you should drain and flush your hot water heater at least once or twice a year. But you may need to do this more often if you live in an area where the groundwater supply has high levels of iron or other particulates.

You can also watch for signs that your hot water heater may need tending to. For example, if you notice discoloration or sedimentation in your water, it may be a sign that your tank is collecting mineral deposits, such as lime, magnesium, and calcium. 

A good test is to compare the output from your hot and cold water faucets. It will be easier to do this if you collect water from the hot and cold faucets in clear glasses for a side-by-side comparison. If only the hot water is discolored or contains sediment, then that’s a strong indication that it’s your hot water heater, not the water supply in general.

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