Anatomy of a Gas Water Heater (Tank type)

Tank Drain Valve
The hot water tank can build up sediments in the bottom of the tank if left unmaintained and by draining the tank using the tank drain valve these sediments cannot build up. And if you don't have sedimentation then that helps to prolong the life of your tank and improve your water quality.

Prepare the tank for flushing by performing the following steps:

Turn off power to an electric water heater. Do this by turning off the circuit breaker or fuse powering the heater.

Turn gas pilot control valve to "pilot" setting.

Shut off water supply to water heater.

Open nearest hot water faucet.

Attach hose to drain valve.

Follow these steps to flush the water tank.