Why Is My Water Heater Making Popping or Knocking Noises?

What are the 4 causes of water heater noises?

The 4 causes of water heater noises are listed below.

• Sediment on the tank floor traps water that boils and pops.
• Scale on an electric heating element makes a hissing or crackling sound.
• Water hammer in the pipes knocks when a valve closes fast.
• Expansion of the tank and pipes ticks as the water heats.

Is a popping water heater dangerous?

No, a popping water heater is not dangerous on its own, but the sediment behind the noise overheats the tank floor and shortens the life of the water heater.

What should you do about water heater noises?

The 4 things you should do about water heater noises are listed below.

1. Listen for where the noise starts: the tank, the element or the pipes.
2. Check the age of the water heater on the label.
3. Book a tank flush to remove the sediment.
4. Call a plumber when the noise comes with leaks or no hot water.

When should you call a plumber?

You should call a plumber in the 4 situations below.

• The noise comes with a leak.
• The water heater is more than 10 years old.
• Hot water runs out faster than before.
• Flushing does not stop the noise.

Related plumbing problems and next steps

How much does the plumbing repair cost?

The plumbing repair cost depends on the cause: a flush or element change is a repair of $222–$990, and a worn-out tank costs $882–$1,810 to replace, according to HomeAdvisor. Water heater repair prices and local plumbers are on the water heater repair in the Lancaster area page.

What is a related plumbing problem?

A related plumbing problem is hard water lancaster pa, and the hard water lancaster pa guide lists its causes and first steps.

Written and fact-checked by the Lancaster PA Plumbers editorial team using HomeAdvisor, EPA WaterSense and City of Lancaster data. Last updated October 29, 2026.