A water heater sacrificial anode rod is a metal rod and is generally screwed into the top of the tank. It’s job is to attract corrosive elements in your potable water. Over time the rods get “sacrificed” for the healthy survival of the heater’s tank and the result can lead to smelly water.
Are you considering replacing your tank model water heater? The guys at This Old House explain how to install a tankless water heater.
Gary Smith says the new water heaters have to accommodate the higher insulation r-values (thermal resistance), making the water heater taller and wider.