You never want to see rust or other types of corrosion appearing on important metal appliances or fixtures. It’s bad news because corrosion weakens metal and eventually causes it to deteriorate and flake away.
Because a water heater is a mostly metal device that holds and circulates water, it’s in jeopardy of rusting. Thankfully, water heaters have special defenses built into them to prevent rust and other types of corrosion from getting an early hold on them. These defenses include the sacrificial anode rod that attracts rust to it rather than the tank; the expansion tank that keeps oxygen out of the main tank (corrosion requires oxygen to trigger the chemical reaction between water and metal); and a glass lining inside the tank.
Yet seeing that your water heater has rust on the outside can still happen. When you see rust on your home’s water heater, does this mean the water heater is finished? Is it time to call us for a water heater replacement?