If you have a traditional water heater with a reservoir tank, you should drain it every six months to a year. Doing so will flush out any minerals and sediments in the water that have made their way into the tank. This will help to prolong the life, and improve the function of the hot water heater. If left alone, these minerals and sediments can calcify on the internal components of the hot water tank which leads to component failures that need repairs or replacement.