Like most appliances, water heaters are taken for granted until there is a problem. While most homeowners have their HVAC equipment maintained on a regular basis, water heaters are usually not checked out.
The quality of the water has a lot to do with the longevity of a water heater. The average lifespan is 10-15 years. Homes with private wells usually have more sediment deposits as compared to Lake Michigan water.
The typical noise we encounter is a rumbling or bumping noise when the burner is on. Sediment settles at the bottom of the tank and with time it solidifies into a mass. As the water is heated this mass starts to float around the bottom of the tank. Every time it hits the side of the tank it creates a noise. This is what most people describes as a rumble or bump. Once the sediment has solidified it is impossible to get rid of it.
Sediment buildup will cause a loss of efficiency and also diminish the lifespan of your heater. If you are planning on replacing your old heater make sure that you drain 1-2 cups of water from the new heater every month. This will eliminate most sediment and prolong the life of the tank.