Why Is Your Water Heater Making That Noise?

You may not realize it, but your water heater is one of the hardest-working appliances in your Tampa home. After all, it must keep water hot and ready to use 24/7. It’s easy to forget this because your water heater works silently in the basement, garage, or utility closet.

If you’ve noticed your water heater popping or making other strange sounds lately, you might be concerned—and rightly so! Here are some common water heater noises and what they might mean.


Do you hear loud popping, cracking, clanking, or other similar noises coming from your water heater? Mineral buildup is the most likely cause. This is the result of hard water depositing calcium and magnesium carbonate over the years.

A popping water heater could be warning you that a thick layer of sediment is building up on the bottom of the tank, blocking heat transfer and lowering water heater efficiency in the process. Ignoring this problem could increase your water heating costs and shorten the life span of the appliance, leading to premature failure.

Fortunately, a plumber can fix this problem by performing water heater maintenance. At Cass Plumbing, we recommend this once a year to help your hard-working appliance operate efficiently and reliably for many years.


Electric water heaters are prone to making this sound. It’s another sign of mineral deposits, as the heating electrodes may hiss when they heat up if they’re covered with sediment.


If you hear banging or booming at startup, turn off your water heater and call a plumber right away for an emergency repair. These sounds could mean that the gas or oil is reigniting when the burner starts, a dangerous situation that increases the chance of explosions.

Sometimes, banging or booming sounds simply mean your water heater is experiencing higher-than-normal thermal expansion. When this is the case, the noise usually occurs when the appliance has to reheat a large quantity of water, such as after the tank has been depleted or turned back on after you get home from vacation. When in doubt, call a plumber to take a look. It may be necessary to add an expansion tank to make the noise go away.


These strange noises may be unnerving, but the cause is usually harmless and easy to fix. First, check for a partly closed control valve at the water heater inlet. Then, consider the size of the exhaust flue. It might be causing a resonant frequency, creating an unpleasant noise when you turn up the temperature on a tankless water heater. A plumber, like Cass Plumbing, can resize the exhaust system if necessary to eliminate the sound.


In most cases, these noises are considered normal. They are the result of thermal expansion as the water heater operates. The sounds most likely come from the heat trap installed in the hot water supply piping downstream from the water heater itself.

If the noises are bothersome, you may want a plumber to check the routing of your hot water piping. If hot water must pass through too-small openings, excessive clicking, ticking, or tapping may occur. Expanding the opening may help.


Whether your water heater is making a popping noise or some other sound, Cass Plumbing can set things right. Our fully trained, licensed, and certified professionals can fix any water heater problem, so call us with complete confidence in our abilities. If it turns out that your water heater has reached the end of its life span, we can suggest a suitable water heater replacement.

For all your water heater repair and water heater replacement needs, Give us a call today at 813-265-9200