Water Heater Making Popping or Rumbling Sounds — Calpe, Valencian Community

Loud popping, rumbling, or kettling sounds from a tank-style water heater are almost always caused by a thick layer of sediment — primarily calcium carbonate — that has settled at the bottom of the tank over years of use. When the gas burner or electric element heats the water through this sediment layer, pockets of water become trapped underneath and flash into steam, producing the popping noise. The sediment acts as an insulating blanket that forces the burner to work harder, raising the tank temperature and accelerating wear on the bottom plate. Left untreated, sediment buildup can reduce heating efficiency by 20–30%, cause the tank to overheat, and eventually corrode through the steel floor, resulting in a leak. A plumber can flush the tank to remove accumulated sediment, inspect the anode rod for corrosion, test the temperature-and-pressure relief valve, and establish a yearly maintenance schedule to prevent recurrence.