Why is my water heater making popping sounds? How to fix the issue before it gets worse

Is your water heater making strange sounds, like popping? Don’t worry, those noises are pretty common, but if you ignore them, the problem can get worse so we’ll break down why your water heater is making those popping sounds and what you can do to fix it before it turns into a bigger headache.

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Important: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Common causes

When your hot water heater is making popping sounds, the noise is usually described as a series of popping or bubbling sounds, similar to water boiling in a kettle. These sounds are often more noticeable when the water heater is actively heating water and may become louder over time.

Several factors can contribute to a water heater making popping noise. Below are the most frequent causes, which can impact both the efficiency and longevity of your water heater:

Sediment buildup in the tank

The most common cause is sediment buildup. Over time, minerals such as calcium and magnesium, especially in areas with hard water, settle at the bottom of the tank. As water heats, steam bubbles form underneath the sediment, causing a popping or bubbling sound as they escape. This buildup can reduce your heater’s efficiency, leading to longer heating times and higher energy bills.

Overheating of water

When sediment accumulates, the water heater has to work harder to heat water through the layer of minerals. This overheating can cause the popping noise to become more frequent and intense. Overheating not only causes noise but also reduces the lifespan of your water heater and increases the risk of damage to the heating elements.

Water expansion

As water heats, it expands, and if there isn’t enough space in the tank to accommodate this expansion, it can create pressure that results in popping or cracking noises. This is more common in older water heaters that don’t have an expansion tank.

Air trapped in the tank

As the water heats and these bubbles move around inside the tank, they create small popping or bubbling sounds. While this may not always signal a major issue, it’s worth checking to ensure the air isn’t being trapped due to other underlying problems, such as faulty valves.

Solutions

The good news is that in most cases, a water heater making popping sounds can be resolved with regular maintenance and a few simple fixes. Here are the most effective solutions:

Flush the water heater tank

1. Turn off the water heater and let it cool down. For gas heaters, set the gas control valve to the “pilot” position.
2. Locate the drain valve on the tank. It is typically located near the bottom and looks like a hose bib with a threaded end.
3. Attach a garden hose to the valve and run it to a drain, utility sink, or outside.
4. Open a hot water faucet in your home to allow air into the system and help with drainage.
5. Open the valve and allow the tank to drain completely. Be cautious as the water can be hot.
6. To further flush the tank, turn the cold water supply back on for a few minutes while the drain valve is still open. This helps to flush out any remaining sediment that may be settled at the bottom of the tank.
7. Once the water runs clear and you have flushed the tank adequately, close the drain valve by turning it clockwise.
8. Disconnect the hose from the drain valve.
9. Turn on the water supply to refill the tank. Keep the hot water faucet open to release any air trapped in the system.
10. For electric heaters, switch the power back on at the breaker box. For gas heaters, set the gas control valve back to the desired temperature.

Install a water softener

A water softener helps prevent sediment buildup by removing minerals from hard water. Reduced sediment buildup leads to a quieter and more efficient water heater.

1. Purchase a water softener suitable for your home’s water needs.
2. Choose a suitable location for the water softener near the main water supply line and close to a drain for discharge.
3. Turn off the main water supply to your home. This is usually located near the water meter.
4. Open faucets in your home to drain any remaining water in the pipes.
5. Connect the inlet and outlet ports of the water softener to the corresponding pipes using compression fittings or soldering, following the manufacturer’s guidelines.
6. Connect the drain line from the water softener to a suitable drain or utility sink.
7. Ensure the drain line is secured and has an air gap to prevent backflow.
8. Plug the water softener into a nearby power outlet.
9. Set the water softener control panel based on the water hardness level in your area.
10. Adjust regeneration settings as recommended by the manufacturer.
11. Open the bypass valve and slowly turn on the main water supply.
12. Flush the system by running water through it to remove any air pockets.

Check and adjust the temperature settings

1. Locate the temperature control on your water heater.
2. For gas water heaters, the temperature control dial is usually located on the gas valve near the bottom of the tank.
3. In electric water heaters, the temperature control is often found behind an access panel on the side of the tank.
4. Before accessing the thermostat, ensure to turn off the power to the water heater at the breaker box.
5. Adjust the temperature to around 120°F (49°C).
6. Some water heaters have two thermostats: one for the upper heating element and one for the lower heating element. Both may need adjustment.

Lowering the temperature reduces strain on heating elements and prevents overheating.

Install an expansion tank

1. Choose an expansion tank that matches the water heater’s capacity and pressure specifications. Refer to the manufacturer’s guidelines for compatibility.
2. Turn off the power supply to an electric water heater or set the gas control valve to the “pilot” position for a gas water heater. Shut off the main water supply to the house.
3. Connect a garden hose to the drain valve at the base of the water heater and drain a few gallons of water to relieve pressure.
4. Install the expansion tank on the cold water supply line near the water heater.
5. Position the tank vertically with the air valve facing upwards.
6. Cut the cold water supply line and solder a tee fitting into the line.
7. Connect the expansion tank to the tee fitting. Ensure the tank’s inlet is connected to the cold water line and the outlet to the water heater.
8. Use pipe straps to secure the expansion tank to the wall or a nearby support structure.
9. Use a tire pressure gauge to check the air pressure in the expansion tank. It should match the water pressure in the plumbing system, typically around 50-60 psi (pounds per square inch).
10. Turn on the main water supply and check for any leaks around the expansion tank and fittings.
11. Once the expansion tank is installed and there are no leaks, restore power to the water heater and turn on the gas supply if applicable.

Frequently asked questions

Why is my water heater making a popping noise?

A water heater making popping noise is usually caused by sediment buildup inside the tank. Over time, minerals like calcium and magnesium settle at the bottom, and when the water heats up, steam bubbles form under the sediment, creating the popping sound as they escape.

Is a popping sound in my water heater dangerous?

While the popping sound itself is not immediately dangerous, it indicates sediment buildup, which can cause the water heater to overheat and become less efficient. Over time, if left unaddressed, it can lead to more significant damage.

How do I stop my water heater from making popping sounds?

To stop your hot water heater from making popping sounds, you should flush the tank to remove sediment buildup. Regular maintenance, such as draining the tank once a year, can help prevent noise and improve the efficiency of your water heater.

Can hard water cause a water heater to make popping noises?

Yes, hard water can cause a water heater making popping noise. The minerals in hard water, like calcium and magnesium, accumulate at the bottom of the tank, leading to sediment buildup, which results in the popping sounds during heating cycles.

Additional information

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