The tutorial How to Troubleshoot and Repair an Electric Water Heater explains how you can diagnose and fix several common water heater problems.
However, some of the repairs involve draining the water heater tank. At least a partial draining the tank is also recommended to be performed every month and a half for the first year and every 6 months thereafter as a preventive maintenance action to help prevent sediment build-up.
Here's how to properly drain the electric water heater:
Turn Off Power
First you must turn off power to the water heater at the electrical panel by disabling the circuit breaker or fuse powering the water heater.
Turn Off Water
Next, turn off the water supply to the water heater. You should find a water shut-off valve at or near the cold water inlet pipe at the top of the tank. Turn the valve clockwise to shut it off. If you cannot find this local shut off valve, then turn off the water supply to the house at the main valve.
Ready the Drain
The drain-cock at the bottom of the water heater tank is a silver or brass colored valve with a threaded end. You can either place a bucket under the drain valve or attach a garden hose to the threaded end of the valve. Run the garden hose to a floor drain if you use that option.
Open Pressure Relief Valve
Flip the lever on the T&P valve into an up position to open it.
Drain All or Part of the Water
- Some drain valves have a handle. Others like the one in the photo shown here have a short handle-less stem with a slot for a flat blade screwdriver.
- Turn the valve counter-clockwise to release a few gallons of water into the bucket or hose for a partial flush.
- If you are doing a complete drain and are using a hose, then let the tank drain until empty.
- If you are using a bucket for a full flush, you should use rubber gloves to avoid getting scalded and then fill the bucket and open and close the valve as many times as needed to empty the tank. Make sure to only partially fill the bucket if you need to tip it to get it out from under the valve spout.
Close the Valve
Once complete, close the valve T&P valve by flipping the lever down and close the drain valve by turning it clockwise. Drain the bucket or remove the hose.
Turn on Water Supply and Power
Now that the draining is complete you can perform any maintenance on the tank. When the repair is complete or if this was just a maintenance flush, then turn the power and water supply to the water heater back on.