How to Flush a Water Heater in 8 Steps

Flushing your water heater annually is one of the simplest maintenance tasks you can do to extend its life and improve efficiency. Over time, sediment builds up at the bottom of the tank, reducing heating efficiency and shortening the unit’s lifespan. Here’s how to flush yours in eight simple steps.

Step 1: Turn Off the Power

For electric water heaters, turn off the breaker. For gas heaters, set the thermostat to “pilot” or turn off the gas supply.

Step 2: Turn Off the Cold Water Supply

Locate the cold water shut-off valve at the top of the heater and turn it clockwise to close.

Step 3: Attach a Garden Hose

Connect a garden hose to the drain valve at the bottom of the tank. Run the other end to a floor drain, outdoors, or into a bucket.

Step 4: Open a Hot Water Faucet

Open a hot water faucet somewhere in the house to prevent a vacuum from forming and allow the tank to drain faster.

Step 5: Open the Drain Valve

Open the drain valve slowly. Be careful — the water will be hot. Let the tank drain completely.

Step 6: Briefly Open the Cold Water Supply

Open the cold water supply for a few seconds to stir up any remaining sediment, then let it drain again. Repeat until the water runs clear.

Step 7: Close the Drain Valve and Refill

Close the drain valve, remove the hose, and open the cold water supply. Let the tank fill until water flows steadily from the open faucet.

Step 8: Restore Power

Once the tank is full, restore power (or gas) and relight the pilot if needed. Wait 30–60 minutes for the water to heat up.

That’s it! You’ve just added years to your water heater’s life. We recommend doing this once a year — set a calendar reminder so you don’t forget.