Over time, this insulates the heating element and causes the 'popping' or 'rumbling' noise you hear.
Common Causes
- Calcium carbonate scale forming as hard water is heated
- Magnesium deposits from dissolved minerals
- Scale accumulating on the heating element, which affects heat transfer
- Scale accumulating in tankless water heater heat exchangers
The Fix
Periodic water heater flushing removes existing sediment. To address the underlying cause, homeowners commonly install a whole-home water softener or, for tankless heaters, a scale inhibitor. ClearFlow installs both.
Related Guides
Related guides
- Water Softener Cost in Myrtle Beach, SC
- Water Softener Installation Near You
- Water Softener Installation in SC & NC
- The SC Homeowner's Guide to Hard Water
Frequently asked questions
Why does my water heater make a popping or rumbling noise?
The sound is commonly caused by water trapped beneath sediment on the tank bottom vaporizing as it heats. It's generally taken as an indication of sediment or scale accumulation in the tank.
How does hard water affect a water heater?
Scale accumulates on the heating element and tank bottom, which affects heat transfer and is a widely documented maintenance concern. Consult your water heater manufacturer's documentation for their guidance on water hardness and maintenance.
Is hard water a bigger issue for tankless water heaters?
Tankless units have narrow heat exchanger passages where scale can accumulate, and many manufacturers publish specific water hardness guidance and descaling requirements in their warranty terms. Check your unit's documentation.
How do I reduce scale in my water heater?
Whole-home water softening addresses the minerals that form scale. ClearFlow also installs scale inhibitors (TAC/template-assisted crystallization) as a salt-free alternative, commonly used with tankless heaters.
How do I find out if hard water is a factor?
ClearFlow provides free in-home water hardness testing so you can see your actual grains-per-gallon reading before deciding on anything. Call (843) 742-1196.