How to Drain a Hot Water Heater

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How to drain hot water heater - tips and recommendation. Step by step guide how to drain. Flushing and draining a heater is an important step for better performance and increased efficiency.

Why to drain hot water heater

There are many reasons why to drain a water heater, and one is the most important; to get rid of the sediment and lime build-up at the bottom of the tank.

Draining a water heater should be part of the regular unit maintenance and is recommended by every manufacturer and experienced plumbers. Draining and flushing the heater's tank should be performed once or twice a year, especially in the area with hard water.

Drain hot water heater to remove the mineral deposits and watch how this little step increases the performance and the efficiency of the unit.

It is necessary to drain a water heater when the tank is leaking, removing the old unit or doing some major service on the unit. If you have to replace an anode rod or dip tube you should drain only a few gallons of water, while on some models when replacing the gas control valve the whole tank has to be emptied.

Another reason for draining is to prevent WH from freezing or when winterizing the unit. In this case, the whole tank should be empty, including the plumbing pipes.

A guide to drain a water heater and the video

This guide applies to conventional tank-type gas heaters, which is slightly different from the electric units.

  • One of the most important steps when draining a water heater is to shut the unit OFF; both gas and electrical part and water supply.

  • Attach the garden hose to the drain valve found in the lower part of the unit and put the other end of the hose either outside or to the appropriate drain. The garden hose is much better and convenient than using the bucket.

  • Before opening the drain valve make sure that the closest hot water tap is open to prevent vacuum creating inside the tank. A TPR valve should also be open to release the inside pressure.

  • Let the hot water run from the tap until it reaches 100 F or less.

  • Keep in mind that it will take some time to drain the heater especially if the tank is 50 gallons or more.

  • Flushing is recommended to clean the tank from the residues.

  • When draining is done follow the procedure for lighting the heater and keep in mind to close the drain valve when filling the unit.

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More tips

Note: The heater should always be easily accessible for operation, maintenance and service.

brass drain valve for water heatersSome storage-tank heaters are equipped with the plastic drain valve while others use the more reliable temper resistant brass drain valve. The thread size is the standard 3/4 inch. They come installed on the unit. Some plumbers are recommending installing ball valves instead, for easier draining.

If flushing the water heater often, you won't see much of the water with the color changed, but if this is the first time after many years of using, be prepared to see brown, rusty water and other deposits, coming either from the sediments and limescale build-up or corrosion.

Drain hot water heater regularly and watch how WH will last for many years while keeping the costs down.

How to maintain a water heater


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