There are several easy and inexpensive ways to increase a water heater’s operating efficiency and longevity. Some things—adding insulation and setting the temperature—have to be done only once. Others, such as flushing the tank and checking the anode rod, should be done annually.
The benefits of caring for your water heater are clear. Setting the thermostats to 120 degrees F. will save energy and reduces the chance for scalding. Flushing sediment from the tank improves efficiency and longevity. And making sure a viable anode rod hangs in the tank will help prevent its inside from rusting out. A used-up rod is far cheaper to replace than a new heater.
Shut off the power or gas and the cold-water supply valve. Open the nearest hot water spigot. Place a bucket under the pipe connected to the temperature-pressure-release (TPR) valve on the top or side of the tank. (This valve opens if the tank pressure gets too high.) Lift the valve’s tab to let some water out, then let go. If water keeps flowing, drain the tank partway, unscrew the old valve with a pipe wrench, and install a new one.
Put a hose to the tank’s drain cock and let out a few gallons of water. Now fit a 1 1/16-inch socket onto the rod’s hex head on top of the heater (or under its top plate) and unscrew the rod. If it’s less than ½ inch thick or coated with calcium, buy a new one, wrap its threads with Teflon tape, put it back in the tank, and tighten securely. Use the segmented rod if headroom above the tank is limited.
Drain the remaining water in the tank into a bucket or outside, and then stir up the sediment on the tank’s bottom by briefly opening the cold-water supply valve. Drain and repeat until clean water comes out of the hose. Close the drain cock, refill the tank, and turn its power back on.