A water heater that makes popping or banging noises usually has sediment buildup at the bottom of the tank. Minerals in the water settle, harden, and trap hot water underneath. When that water turns to steam, it pops through the sediment. A flush may help, but loud banging, leaks, or rusty water need a plumber.

Common Reasons a Water Heater Makes Noises

Sediment buildup: This is the most common reason a tank water heater makes popping, banging, cracking, or rumbling sounds. Small minerals in the water settle at the bottom of the tank as a natural result of heating. Over time, they form a hard layer that makes the water heater work harder.

Hard water: The Triad has hard water in many areas, which means the water carries more minerals. Those minerals can build up faster inside water heaters in Winston-Salem, Kernersville, Greensboro, and High Point homes. Homes on well water can see even faster buildup if the water is not treated before it enters the heater.

Overheating under the sediment: When sediment covers the bottom of the tank, heat gets trapped under it. Water can flash into steam and push through the sediment. That is the popping or knocking sound you hear.

Loose parts or pressure issues: Not every noise is sediment. A loose pipe, loose heating element, or pressure problem can also cause banging. If the sound is sharp, sudden, or getting worse, do not ignore it.

What You Can Try First

If the water has been maintained, a water heater flush may clear out loose sediment. Some homeowners do this themselves with a hose and the drain valve. Be careful and follow the manufacturer’s instructions.

 

If your water heater is older, has never been flushed, or the drain valve looks rusty, do not force it open. Older valves can leak after being opened. A plumber can flush the tank safely and check whether the noise is from sediment or another problem.

It also helps to listen for other symptoms. If the popping noise comes with less hot water than usual, sediment may be taking up space inside the tank. That same buildup can be why your hot water runs out so fast.

When to Call a Plumber

Call a plumber if the banging is loud, the tank is leaking, the water looks rusty, the water heater is more than ten years old, or the noise comes back soon after flushing. You should also call if the pressure relief valve is leaking or if you are not sure how to shut off power, gas, or water to the unit.

What This Costs

Our water heater service starts at $250. The final cost depends on the age of the unit, the amount of sediment, the parts needed, and whether the tank needs maintenance, repair, or replacement.

In the Triad, hard water can make sediment build up faster than many homeowners expect. If your water heater is making popping or banging noises in Winston-Salem, Kernersville, Greensboro, or High Point, our water heater repair and maintenance service team can inspect it, flush it if safe, and explain the next step.