What Does That Rumbling Noise in My Water Heater Mean?
Water Heaters
A quiet water heater is a happy water heater. If yours sounds like a boiling kettle or someone hitting it with a hammer, you have a sediment problem.
The Science of the Sound
Over time, minerals in your water (calcium and lime) settle to the bottom of the tank. The burner is located directly underneath this layer.
As the burner heats up, water trapped underneath the sediment layer boils into steam bubbles. When these bubbles escape the sediment layer and hit the cooler water above, they collapse or 'implode' loudly. That is the popping sound you hear.
Why It's Bad
- Overheating: The sediment acts as insulation, forcing the burner to run longer to heat the water. This can damage the metal tank bottom.
- Higher Bills: Your unit becomes less efficient, using more gas or electricity to do the same job.
- Leaks: The localized overheating creates stress fractures in the steel tank.
The Solution
You need to flush the tank immediately to remove the sediment buildup. If the noise persists after a thorough flush, the sediment may have hardened into 'scale,' and it might be time for a replacement.