The anode rod in the water heater is often called the sacrificial rod. It earns the name because it's sole purpose is to attract corrosive elements in the water so that these elements corrode the rod and not the tank itself. The rod needs to be replaced periodically, and the following signs indicate when it is replacement time.
1. Water Discoloration
Corrosion can stain the water that comes out of the heater an orange-brown color. Corrosion staining of the water occurs when the anode rod is no longer working, so rust and corrosion are beginning to damage the liner of your water tank. Once you notice water discoloration, you need to call in a plumber immediately so they can flush the tank and replace the rod before further damage occurs.
2. Foul Odors
A failing rod can also cause the water that comes from the taps to produce an odor reminiscent of rotten eggs. The odor is caused by a bacteria that produces a sulfuric byproduct in the water. The bacteria blossoms when the water becomes more acidic due to the increase in corrosiveness in the tank due to the old anode rod. Flushing and disinfecting the tank, replacing the rod, and turning up the water temperature solves the problem.
3. Increased Scale Buildup
Mineral scale buildup can damage the tank and heating elements, as well as clog pipes, and ruin water fixtures. Scale is one of the corrosive substances that anode rods help prevent, so if you are noticing increased limescale buildup around your water fixtures or on your dishware after washing, then a failed anode rod could be the culprit. Replacement of the rod should reverse the problem.
4. Noise Increase
All water heater tanks make some noise, such as mild pops as the unit flexes due to the heat. The problem is if your unit begins popping and cracking more often and more loudly. The cause of the increased popping is scale buildup on the inside of the tank cracking and falling off the walls. Much like the scale at the fixtures, scale in the tank also indicates that the anode rod is due for replacement.
5. Water Heater Age
Anode rods have a finite lifespan, which will vary depending on your water quality but usually is only a few years. Your plumber can let you know the expected lifespan for your particular anode rod. If your water heater is approaching the age that coincides with the life expectancy of the anode rod, then it is time to have the rod replaced.
Contact a plumber to learn more about maintaining the health and function of your water heater system.