How to flush a water Heater


For a healthy water heater, you should flush it every year. Over time, sediments, such as minerals and debris, accumulate in the water heater. They can pile up and become a solid concrete mass causing all sorts of problems. They are corrosive; they can eat through the tank and cause a leak. They can cause fluctuations in the water temperature. They can clog the drain. They can make your water heater noisy. They can shoot up your energy bills, and can eventually lead your water heater to fail.

To avoid all such problems, you should flush your water heater every year. Flushing involves emptying the water heater tank and then agitating the sediments accumulated so they can be flushed out of the tank. It is all quite simple really. You can do it yourself and save more than $100 every year.

Step 1: Turn off the Power Supply

Gas: At the lower side of the tank, there should be a temperature control dial. You can turn the dial off or at the pilot setting. If you turn the dial off, you will need to relight the pilot light.

Electric: Go to your breaker panel. Locate your water heater breaker and switch it off. Pretty simple.

Note: If you don't turn off the power supply, you will be heating an empty tank once you drain the water. This can melt and ruin your water heater because you will be heating an empty water heater.

Step 2: Turn Off the Cold Water Supply

Next, you'll need to stop the flow of cold water into the tank. At the top of your water heater, you'll find two pipelines, one of which will have a valve. Rotate this valve until it's perpendicular to the pipe to shut off the water supply.

Step 3: Connect a hose

Your water heater should have a drain spigot located towards the bottom. Securely attach one end of a garden hose to this spigot. The other end should be positioned inside a bucket to collect the hot water and sediment, allowing you to inspect the drained water and avoid spillage. Once the hose is secure, open the drain valve. Don't be surprised if water doesn't immediately flow out - this is due to the lack of air inside the tank. You must let the air inside the tank before the water can drain out.

Step 4: Open a hot water faucet

If we open the valve now, since there is no water being allowed into the tank, it would act like a straw with your finger over the end of it, and no water would flow out. Therefore, we need to allow air to get into the system. We need to open a hot water faucet in the house. This would allow air to travel in from the faucet side so that the water can drain out of your tank.

Step 5: Open the Drain Valve

To open the drain valve, turn the drain valve handle parallel to the garden hose. If you do not see a valve handle, there is probably a screw head for opening the drain valve. Take a flat-head screwdriver and turn the screw-head so that it is parallel to the garden hose.

If you don't hear any water flowing or air being sucked into the system. Then you might have a backflow preventer valve installed somewhere into your plumbing. This prevents air from entering into your system. As a result opening a faucet is not enough to let the air into the system. We will need to open our pressure relief valve.

Step 6: Open the Pressure Relief Valve

Relief Valve is a safety device. It opens up if the pressure gets too high inside the tank to air and water out, relieving the pressure. If you open the relief valve, however, air can also flow into the tank through the valve.

Relief valve is always located at the upper side of the tank. You have to open it like an old school suitcase. You will need to lift the lever up. But before you open it, it's a good idea to place a bucket under it. In case water comes out through the relief valve. Open the relief valve. Immediately, you will hear the air rushing into the tank and water flowing out through the drain valve below.

Step 7: Inspect the Draining Water

It is a good idea to inspect the water coming out of the tank to assess the health of your water heater. Wait for 15- 20 minutes to let the water drain out.

If water is not draining out of the tank, your drain valve is probably clogged. Sometimes, sediment scales can get loosened up and block the drain port. To unclog the path, blow into the hose one or two times. This should push the scale back into the tank. Be wary, because the hot water coming out is scalding.

If you still do not see water coming out, the sediment has probably accumulated to the point that it is blocking the valve. If that's the case you will need to call a plumber.

Word of Caution: Water draining out is scalding. So be careful. Don't let your dogs or child play in it. Don't use it to water your garden.

Step 8: Flush in Burst

Draining is such a gentle process that it does not agitate much of the sediment. To agitate the sediments, we will open the cold water supply that we closed in Step 2.

First you need to empty the drain bucket. Go back to the pipeline on top of the water heater, and turn the valve so that it is parallel to the pipeline. Immediately you will hear water hitting the bottom of the tank, agitating those stubborn sediments at the bottom. Close the valve after 15-20 seconds. Let the water drain out. Go to the bucket and inspect the water. You will probably see plenty of debris floating around. We will be flushing the water heater one more time.

Empty the bucket again. And repeat the flushing: open the water supply for 15-20 seconds, let the water drain out into the bucket, and inspect the bucket again. If the water still has plenty of debris, repeat the flushing. Keep flushing until your water comes out clear.

If the water is mostly clean, congratulations you have successfully flushed your water heater like a professional.

Step 9: Restart the Water Heater

  • Turn off the drain valve and remove the hose.
  • Open the cold water supply, and wait until the tank is half full
  • Close the relief valve by pushing the arm downward.
  • Dial the thermostat back to the desired temperature setting.
  • Finally, open a hot water faucet to let the air flow out of the system. Once the water starts flowing smoothly, you can close the faucet.