Water Heater Making Noise? What Each Sound Means and How to Fix It
July 5, 2026 · 5 min read · By Deep Dive Plumbing Maryland
A noisy water heater is your system trying to tell you something. The type of noise — popping, banging, hissing, or rumbling — points to a specific problem. Most are fixable. Some are urgent. Here is how to decode what you are hearing.
Water Heater Noise Diagnostic Guide
Popping or rumbling
ModerateCause: Sediment buildup on the bottom of the tank or heating element
Fix: Flush the tank. If the noise persists, the element may need replacement.
Banging or knocking
ModerateCause: Thermal expansion in pipes, or water hammer
Fix: Check expansion tank. Install water hammer arrestors if needed.
Hissing
HighCause: Condensation dripping on the burner (gas), or a small leak
Fix: Inspect for leaks. If no leak, condensation on a new heater is normal.
Screeching or whining
LowCause: Partially closed valve restricting water flow
Fix: Check all valves on the cold water supply line — make sure they are fully open.
Ticking or tapping
LowCause: Thermal expansion of pipes as they heat and cool
Fix: Normal in many homes. Pipe straps can reduce noise if bothersome.
Sizzling
HighCause: Water dripping on the burner (gas) — possible T&P valve discharge
Fix: Inspect T&P valve and expansion tank. Call a plumber.
Frequently Asked Questions
Why does my water heater make a popping noise?
Popping sounds from a water heater are almost always caused by sediment. As the tank heats water, steam bubbles form under the sediment layer and pop through it — creating the popping or rumbling sound. This is more common in hard water areas like Calvert and Anne Arundel County where mineral deposits accumulate quickly. Flushing the tank removes the sediment and usually eliminates the noise.
Is a noisy water heater dangerous?
Most water heater noises are not dangerous, but they are warning signs. Popping and rumbling indicate sediment buildup that reduces efficiency and shortens tank life. Hissing or sizzling can indicate a leak or T&P valve issue that needs immediate attention. Banging or knocking may indicate a water hammer problem that can damage pipes over time.
My water heater is new and making noise — is that normal?
Some noise from a new water heater is normal. Ticking and tapping as pipes expand and contract is common. Hissing from condensation on the burner of a gas heater is normal for the first few days. However, loud banging, popping, or persistent hissing on a new heater should be investigated — it may indicate a water hammer issue or a problem with the installation.
Related Resources
