Ans. If this happens, this means your tank needs draining and flushing. If you don’t do this the water tank efficiency of heating water will get low and then, in the long run, you will need to change the hot water tank fully. The popping noise is caused by the water boiling underneath the tank. The noise coming from the water tank is harmless alone but the sediments can cause damage to the electric heating element and eventually cause a leak. To fix this drain and flush the hot water tank.