How To Flush Your Water Heater

Flushing your water heater gets rid of mineral deposits and gunk that collect in the heater, and it helps your water heater run more efficiently and longer. Here’s how to flush your water heater.

Turn Off the Heat Source

The first step is to turn off your water heater’s heat source. How you should do this depends on the type of water heater you have.

  • Electric
    For electric models, simply find the water heater’s circuit breaker in your home’s breaker box. If you don’t know which breaker it is, they should all be labeled on the inside of the box’s door. Flip the appropriate breaker to the “off” position.
  • Gas
    For gas models, turn the water heater’s thermostat to the “pilot” position. The thermostat will be located somewhere near the bottom of your water heater.
    NOTE: If you turn the thermostat to so it’s fully off, you’ll need to also turn off the gas supply. Then you’ll have to turn the gas back on and relight the pilot when you’re done. It’s easier to just leave the thermostat on “pilot.”

Set Up the Plumbing

Second, you’ll need to adjust a couple of plumbing valves.

  • Turn off the water heater’s cold water supply, which should be located near the top of the water heater.
  • Then, turn on a sink or bathtub hot water. You’ll want to leave this faucet on throughout the draining process so a vacuum doesn’t form inside the water heater.

Drain the Water Heater

The water you are draining out of the heater has to go somewhere. Outside is best. Depending on your particular situation, one of the following may be your best choice:

  • Connect a hose to the water heater’s drain spigot and run it outside.
    This spigot will be located near the bottom of the water heater.
    If your water heater is on the ground floor, you won’t have any trouble running the hose outside.
    If your water heater is in the basement, you may need to also connect a portable pump so the water leaves the hose.
  • Drain the hose into a bucket, and carry the bucket outside when it fills up. This would require constantly turning the drain spigot on and off, though, and you’d need to make a lot of trips.
  • Run the hose to your basement floor drain. If you use this option, run the water through a sieve or other device to remove sludge that may lodge in the floor drain.
  • Another option, if you have a sump pump, is to run the hose into the sump pump. If you use this option, be sure to run the drain water through a sieve first to remove debris that might damage the sump pump itself.

With the hose directing water outside, follow these steps:

  1. Open the drain spigot so water begins draining.
  2. Let the water drain until it’s clear and contains no sediment.
  3. After the water runs clean, open the water heater’s cold water supply.
  4. Let the water continue to drain until it’s once again clear and has no sediment.

The water heater is flushed.

Finish the Task

To clean up, turn off the drain spigot and disconnect the hose. Turn off the sink or bathtub faucet, and turn the heat back on. You should have clean, hot water in a few minutes.

Flushing your water heater involves a bit of time and effort, but doing this task regularly will extend the life of your water heater.

You might also like:

Download our Home Maintenance Schedule to keep up on this and other home maintenance tasks.

Download home maintenance schedule

Flushing your water heater gets rid of mineral deposits and gunk that collect in the heater, and it helps your water heater run more efficiently and longer. Here’s how to flush your water heater.

Turn Off the Heat Source

The first step is to turn off your water heater’s heat source. How you should do this depends on the type of water heater you have.

  • Electric
    For electric models, simply find the water heater’s circuit breaker in your home’s breaker box. If you don’t know which breaker it is, they should all be labeled on the inside of the box’s door. Flip the appropriate breaker to the “off” position.
  • Gas
    For gas models, turn the water heater’s thermostat to the “pilot” position. The thermostat will be located somewhere near the bottom of your water heater.
    NOTE: If you turn the thermostat to so it’s fully off, you’ll need to also turn off the gas supply. Then you’ll have to turn the gas back on and relight the pilot when you’re done. It’s easier to just leave the thermostat on “pilot.”

Set Up the Plumbing

Second, you’ll need to adjust a couple of plumbing valves.

  • Turn off the water heater’s cold water supply, which should be located near the top of the water heater.
  • Then, turn on a sink or bathtub hot water. You’ll want to leave this faucet on throughout the draining process so a vacuum doesn’t form inside the water heater.

Drain the Water Heater

The water you are draining out of the heater has to go somewhere. Outside is best. Depending on your particular situation, one of the following may be your best choice:

  • Connect a hose to the water heater’s drain spigot and run it outside.
    This spigot will be located near the bottom of the water heater.
    If your water heater is on the ground floor, you won’t have any trouble running the hose outside.
    If your water heater is in the basement, you may need to also connect a portable pump so the water leaves the hose.
  • Drain the hose into a bucket, and carry the bucket outside when it fills up. This would require constantly turning the drain spigot on and off, though, and you’d need to make a lot of trips.
  • Run the hose to your basement floor drain. If you use this option, run the water through a sieve or other device to remove sludge that may lodge in the floor drain.
  • Another option, if you have a sump pump, is to run the hose into the sump pump. If you use this option, be sure to run the drain water through a sieve first to remove debris that might damage the sump pump itself.

With the hose directing water outside, follow these steps:

  1. Open the drain spigot so water begins draining.
  2. Let the water drain until it’s clear and contains no sediment.
  3. After the water runs clean, open the water heater’s cold water supply.
  4. Let the water continue to drain until it’s once again clear and has no sediment.

The water heater is flushed.

Finish the Task

To clean up, turn off the drain spigot and disconnect the hose. Turn off the sink or bathtub faucet, and turn the heat back on. You should have clean, hot water in a few minutes.

Flushing your water heater involves a bit of time and effort, but doing this task regularly will extend the life of your water heater.

You might also like:

Download our Home Maintenance Schedule to keep up on this and other home maintenance tasks.

Download home maintenance schedule