How to Drain Hot Water Heater

Drain hot water heater tips and recommendation. Step by step guide how to drain. Flushing and draining a heater is 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; sediment and lime build-up on the bottom of the tank. Draining a water heater should be part of the regular WH maintenance and is recommended by every manufacturer and most 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 few gallons of water, while on some models when replacing the gas control valve the whole tank has to be empty.

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.

emergency plumber

A guide to drain a water heater

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

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

  • 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 to drain lots of water.

  • Before you open the drain valve make sure than the closest hot water tap is open so you won't create a vacuum inside the tank. 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.

Note: Your heater should always be easily accessible for operation and service.

brass drain valve for water heatersSome storage-tank heaters are equipped with the plastic drain valve while others are using 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 for easier draining.

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

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


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