Water Heater Knocking Sound: DIY Solutions for a Quieter Home

water heater knocking sound

πŸ’§ Water Heater Knocking Sound: DIY Solutions for a Quieter Home

Water heaters are an essential part of our daily lives, providing hot water for our showers, dishes, and laundry.

However, many homeowners have experienced a knocking sound coming from their water heaters, which can be quite alarming.

In this article, we’ll explore the reasons why your water heater may be making a knocking sound and what you can do to fix the issue.

πŸ’§ Understanding the Knocking Sound in Water Heaters

The knocking sound in water heaters is caused by a variety of factors, including sediment buildup, water hammer, and pipe expansion and contraction.

Each of these issues can cause different types of noises, which can range from gentle tapping to loud knocking sounds.

πŸ“— Related Reading: Why Is My Hot Water Heater Making Noise When Water Is Off?

πŸ”₯ How Water Heaters Work

Before we dive into the causes of knocking sounds in water heaters, it’s essential to understand how they work.

Water heaters typically use gas or electricity to heat water, which is then stored in the water heater tank until it is needed.

When you turn on your hot water faucet, the hot water travels through pipes and into your home.

πŸ“— Related Reading: Tank vs Tankless Water Heater: The Great Water Heater Debate

πŸ”₯ Common Causes of Knocking Sounds

One of the most common causes of knocking sounds in water heaters is sediment buildup.

This occurs when minerals and other debris collect at the bottom of the water heater tank, creating a thick layer that can impede the heater’s performance.

Another common cause is the water hammer phenomenon, which happens when water travels through pipes and causes them to vibrate or bang against other surfaces.

Finally, the expansion and contraction of pipes due to temperature changes can also cause knocking sounds.

πŸ”₯ Identifying the Source of the Noise

If you’re experiencing knocking sounds from your water heater, it’s important to identify the source of the noise before attempting to fix the issue.

Start by checking for loose pipes or valves, which can cause banging noises.

If that doesn’t help, try flushing the tank to remove any sediment buildup.

If these steps don’t work, you may need to call a professional plumber to diagnose the problem.

πŸ’§ Sediment Buildup and Its Effects

limescale on water heater element

Sediment buildup is a common cause of knocking sounds in water heaters, but it can also lead to other issues.

Over time, a thick layer of sediment can form at the bottom of the tank, reducing the amount of available hot water and making it harder for the heater to maintain a consistent temperature.

This can lead to higher energy bills and more frequent repairs.

πŸ”₯ What Causes Sediment Buildup

Sediment buildup is caused by minerals and debris that are naturally present in most water sources.

As the water is heated, these particles settle at the bottom of the tank, creating a thick layer that can impede the heater’s performance.

The problem is most common in areas with hard water, which contains a higher concentration of minerals.

πŸ”₯ How Sediment Leads to Knocking Sounds

When sediment builds up in a water heater, it can create hot spots that cause the tank to expand and contract.

This movement can create knocking sounds, which are often loud and alarming.

Additionally, the sediment can cause the water to boil, which can also lead to banging noises.

πŸ”₯ Preventing and Removing Sediment

The best way to prevent buildup is to have your water heater flushed regularly by a professional plumber.

This process involves draining the water heater’s tank and removing any debris that has accumulated at the bottom.

βœ… PRO TIP: If you live in an area with hard water, you might want to consider a water softener or water filtration system, which will reduce sediment from entering the hot water heater in the first place.

πŸ’§ Flushing Your Water Heater Tank With These Easy Steps

water heater repair

Flushing your hot water heater can significantly reduce the likelihood of hearing knocking sounds and prolong the life of your tank.

Follow these easy steps to flush your hot water heater:

  1. Turn off the power supply to the water heater. If it’s a gas water heater, set the gas valve to “pilot”. If it’s an electric water heater, flip the circuit breaker off.
  2. Turn off the cold water valve.
  3. Release excess pressure by operating the pressure relief valve.
  4. Connect a garden hose to the water heater’s drain valve at the bottom of the tank and run the hose outside to a suitable draining location.
  5. Open a hot water faucet in your home to allow air into the tank.
  6. Open the drain valve and let the water drain out of the tank completely.
  7. Once the tank is empty, close the drain valve and turn on the cold water supply valve.
  8. Allow the tank to fill completely and then turn on a hot water faucet to let any remaining air out.
  9. Once the water is flowing smoothly, turn the power supply back on.

By flushing your hot water heater regularly, you can help prevent knocking sounds and other issues caused by sediment.

πŸ’§ Water Hammer Phenomenon

woman with hammer

The water hammer phenomenon is another common cause of knocking sounds in water heaters.

This popping noise occurs when water travels through pipes at high pressure and then suddenly stops, causing the pipes to vibrate or bang against other surfaces.

The noise can be quite loud and may occur when you turn off a faucet or when your dishwasher or washing machine cycles.

πŸ”₯ What is Water Hammer?

Water hammer occurs when water travels through pipes at high speed and then suddenly stops.

This creates a shock wave that can cause the pipes to vibrate or bang against other surfaces.

πŸ”₯ How Water Hammer Causes Knocking Sounds

When your water heater is affected by a water hammer, it may create knocking sounds when the flow of water is suddenly interrupted.

This can be especially problematic in older homes, where the pipes may not be securely fastened in place and are more likely to vibrate or move.

πŸ”₯ Solutions for Water Hammer Issues

If you’re experiencing water hammer issues, there are several solutions you can try.

One option is to install water hammer arrestors, which are devices that absorb the shock of the water when it’s shut off.

Another solution is to check your pipes for loose or unsecured sections and secure them in place.

Finally, installing a pressure-reducing valve can help to reduce the overall water pressure in your home and prevent water hammering from occurring.

πŸ’§ Expansion and Contraction of Pipes

plumbing fixing burst pipes

The expansion and contraction of pipes due to temperature changes can also cause knocking sounds in water heaters.

When the metal pipes expand or contract, they can shift and rub against other surfaces, creating a tapping or knocking sound that may be more noticeable in the quiet of the night.

πŸ”₯ Temperature Changes and Pipe Movement

The movement of pipes due to temperature changes can cause knocking sounds when the metal rubs against walls or other surfaces.

This is because metal expands when it’s heated and contracts when it’s cooled, which can create movement in the pipes.

πŸ”₯ How Pipe Movement Creates Knocking Sounds

When pipes move due to temperature changes, they can create a tapping or knocking sound as they rub against other surfaces.

This noise may be more noticeable when the pipes are exposed, such as in a basement or crawl space.

πŸ”₯ Securing Pipes to Minimize Noise

The best way to minimize pipe movement and reduce knocking sounds is to secure the pipes in place.

This can be done using pipe straps or hangers, which help to prevent movement and keep the pipes in place.

Additionally, insulating your pipes can help to reduce temperature changes and prevent expansion and contraction.

πŸ“— Related Reading: How to Reduce Water Pipe Noise in Your Home

πŸ’§ Conclusion

Phyxter Approved Logo on Service Truck

If your hot water heater is making knocking sounds, it’s important to understand the causes so that you can address the issue quickly.

Whether it’s sediment buildup, water hammer, or pipe expansion and contraction, there are solutions available to help minimize noise and improve the performance of your water heater.

By taking care of your water heater, you can ensure a steady supply of hot water and avoid costly repairs down the road.

If you’d like to expand your knowledge about your home’s plumbing systems, feel free to explore our other plumbing articles.

πŸ“— Related Reading: Your Quick Guide to Tankless Water Heater Maintenance

Russell Jones

Russell, a native Australian and VP of Operations at Phyxter Home Services, is also part-owner of Vernon Air Conditioning, Plumbing, and Electrical Services. When he's not busy with work projects and renovations, Russell enjoys putting his vast knowledge of home improvement to good use by sharing his tips and tricks.

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