Why is My Well Water Pump Making a Loud Banging Noise?

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Banging or other loud sounds from your well pump can be concerning. Here, we’ve shared the 10 most likely reasons for a banging well water pump, and how to fix the problem.

📌 Key Takeaways:

  • A banging well pump might be caused by a clogged system, cavitation, a bad motor, a damaged impeller, or trapped air.
  • The different noises that you might hear from a well pump are knocking, clunking, humming, grinding, clicking, banging, rattling, and screeching.
  • All of these noises, especially when persistent, suggest that your well pump has a problem.

🪛 10 Causes Of A Banging Well Pump Noise – And How To Resolve

Read on to learn the 10 reasons why your well pump might be making a loud noise, and how to resolve each of these problems.

1) Clogging In The System

The impeller in your well system might be clogged by rust and sediment particles. High-sediment well water may eventually wear out the circulating pump, resulting in excessive noise.

If your water system is clogged, the submersible pump will short cycle, then make banging or grinding noises when the water supply pipes become blocked.

✅ How To Resolve

To resolve an issue with a clog in the system, follow these steps:

  1. Check that the pump is receiving electricity.
  2. Program the pump to run for 15 minutes, then switch it off.
  3. Remove the pump from your well and check it over (or get a professional inspection) to look for clogs or debris.
  4. Clean away any visible debris and use a wire brush and a damp cloth to clean the screen and intake.
  5. Put the pump back in your well and switch it on.
Plumber removing a well water pump

2) Cavitation

Another potential cause of a loud noise from your well pump is cavitation. This occurs when rapid changes in pressure cause tiny bubbles of water to vaporize, forming cavities on the impeller.

Cavitation is usually caused by a lack of pressure in the pump’s suction end, which could be due to a pipe blockage on the suction side, clogged filters, poor piping design, or conditions not meeting NPSH (net positive suction head) requirements.

The low-pressure air bubbles formed by cavitation may be the cause of the loud noises from your pump.

✅ How To Resolve

If you suspect your well pump has been damaged by cavitation, turn it off immediately and contact a professional to come and inspect your pump. Don’t use the pump again until it’s repaired and you’re given the all-clear by the professional.

In some cases, the pump might be beyond repair and you’ll be advised to buy a new one.

3) Excessive Wear On The Bearing Assemblies

A loud screeching sound occurs in well pumps that have excessive bearing wear inside the motor or on the assembly. This problem only applies to pumps that have bearing assemblies (any pump with an electric motor).

You might need to replace your pump’s bearing assembly if it’s starting to fail. Luckily, this job is relatively easy and expensive – although we still recommend hiring an expert if you’re not confident in your own DIY skills.

If the motor bearings wear out, you’ll have to buy a new motor entirely since the bearings aren’t available separately.

✅ How To Resolve

It’s important to address an issue with bearing failure as soon as you notice it to prevent damage to any of the other components in the well pump.

Replace the bearing according to the instructions in your user manual. Call a technician if you need professional help.

You might need to reach out to the manufacturer if you can’t fix the bearing.

Well Pump Maintenance

4) Failing Pump Motor

There are some specific noises to listen out for that suggest your well pump motor is failing. A buzzing noise may be the sound of the motor attempting to switch on.

A failing motor will likely have obvious signs other than the noises it’s making. Your home’s water pressure will probably drop or become nonexistent, and you’ll have insufficient water flow in your home, as the motor struggles to power the pump to draw water from your well.

✅ How To Resolve

There are a few different issues that you may need to resolve with a bad motor. You might be able to repair the motor or hire a professional to do the repair work for you.

In some cases, it might actually be cheaper and easier to replace the motor entirely.

5) Damaged Impeller

If your pump’s intake is using an insufficient filter, sand, silt, and other debris from the well aquifer may be able to enter the pump housing.

When this sediment gets into the impeller, it could cause damage, leading to excess noise when the pump is cycling.

A failing impeller will prevent the pump from cooling the engine, leading to overheating and loud noises.

✅ How To Resolve

A damaged impeller is another problem that could cause additional damage to your well pump, so if you think this is the cause of the banging or rattling sound, act fast.

Turn off and flush your pump immediately, then disassemble and clean the pump to remove the accumulated debris.

If your pump’s intake filter is worn, or there isn’t a filter at all, replace or install a filter to prevent harm to the impeller going forward.

Debris on well pump impaler
Matt, Public domain, via Wikimedia Commons

6) Incorrectly Sized Pump

An incorrect pump size – either a pump that’s too big or a pump that’s too small for your well – will cause a loud noise inside your system.

There are a few reasons why your pump could be oversized or undersized. The well installer might have made an error when designing the well, or the well pump might have been deliberately oversized to account for pipe corrosion that would require more pump head or allow for the well to expand in later years.

No matter what the cause of an incorrectly sized pump, it may result in noises due to excessive vibration, causing the joints and connections to loosen.

✅ How To Resolve

Ask a professional to help you determine whether your pump is oversized or undersized.

If the pump is too big, there are a few things you can do to remedy the issue:

  • Reduce the impeller diameter
  • Install a flow recirculation line
  • Throttle the valves on the pressure side until you no longer hear the noises
  • Reduce the pump speed
  • Remove the control valves and install a variable frequency drive

If the pump is too small, there’s not a lot you can do to make things better. An undersized pump won’t be able to meet your water demands or perform the duties you expect of it. It might also lead to deadheading, which is another source of noise and damage, and might burn out the motor.

A short-term solution is to see if there’s space in the pump to replace the motor with a larger, more powerful one. Ultimately, an issue with an undersized pump can only be resolved by replacing the pump with a bigger model.

7) Incorrect Speed Setting

If you’ve set your well pump’s speed setting incorrectly, this could be another cause of unusual pump noises in your well.

An older pump might have one or two flow settings, while a modern, high-quality pump should have three. Older pumps tend to be louder than new pumps for this reason: they can’t operate as efficiently, so they emit a louder humming noise.

✅ How To Resolve

You can resolve an issue with a humming sound in your pump by adjusting the pump’s flow setting.

Usually, turning the setting down one level will do the trick. After you’ve lowered the setting, check that the tower rails and radiators are still reaching the optimal temperature. If they are, then you can leave the setting as it is.

Well water electronic pressure switch

8) Air In The System

If your well water pump doesn’t have an air separator, there’s a good chance that you’ll experience air in the system at least once throughout the pump’s lifespan.

There are a few ways that air can enter the pump, including due to a leaky suction line or through free-falling discharge.

Air in the system will lead to excessive vibration, causing the pump to make a lot of noise. The longer the air stays in the system, the poorer the pump’s performance.

✅ How To Resolve

There are two simple steps to resolve an issue caused by air in the system: by inspecting the water lines and bleeding the pump.

In wells with modern pumps, this is easy because of the built-in bleeder valve. Open the valve gradually until you can hear a hissing sound, then wait for the noise to cease and a small amount of water to leak out. This tells you that all the air has been released, and you can shut the valve.

Now you need to prevent air from re-entering the pump. Check the pump’s installation, since even a slight issue with misalignment may allow air to enter the pump.

9) Installation Issues

A well pump that isn’t installed correctly will also create loud or unusual sounds in your well system.

Your pump might have been installed incorrectly if a non-professional handled the install, or the pump might be unsuitable for installation in your well system.

✅ How To Resolve

The only way to resolve an incorrect pump installation is to remove and re-install the pump. It’s best to hire a professional to do this, since they can confirm whether or not the pump was installed incorrectly and check that the pump is suitable for your well.

A professional will follow the steps outlined below to remedy a poor pump installation:

  1. Shut off power to the well and ground the system.
  2. Remove and reinstall the pump and control box.
  3. Fill the well with water and connect the pump to the water tank.
Plumber conducting a well-pump inspection

10) Water Hammer

The final potential cause of a loud banging noise in your well is a water hammer.

A water hammer occurs due to a sudden change in flow rate, which is usually caused by the pump tripping and quickly starting up, or a valve closing suddenly, sending a shock wave down the water pipe.

There are a few different noises that you might hear due to a water hammer, including pounding noises and banging or clanking sounds, typically when the faucets are shut off.

✅ How To Resolve

To determine whether the sound comes from a water hammer, try partially closing your water supply valve. If you can no longer hear the sound, it’s probably a water hammer.

The only way to resolve a water hammer is to address the cause. Hire a professional well contractor to inspect your well and help you get to the bottom of the issue.

🔊 Common Noises From Well And What They Mean

Let’s finish by looking at some of the common noises you might hear from your well – either from the water pump or another part of the system – and what they might mean.

  • Banging – A banging sound suggests that the pump is cycling on and off. Trapped air in the system may cause a pressure change that rattles your pipes.
  • Screeching – A screeching or screaming sound is usually caused by vibrations in the pump due to failed bearings.
  • Clicking – A clicking sound might be normal, caused by the clicking of the pressure switch when the pump cycles on and off. If the pump itself is making these noises, it might be short cycling. Check your well water pressure tank for clogs or if it is waterlogged.
  • Humming – A humming sound could be caused by a leaking foot valve or a pump system that’s running dry due to a lack of water in the well.
  • Rattling – A vibrating, grinding, or rattling sound may be caused by a faulty assembly or debris in the well pump.
  • Clunking – A clunking sound is usually heard when the pump switches on, and may be caused by a failing check valve, a problem with the pump relay switch, or loose piping.
  • Knocking – The sound of knocking in well pumps is usually caused by worn valves that prevent water from being properly discharged.

📑 Final Word

Well pumps don’t last forever, and when a pump fails or an issue occurs with one of the pump’s components, an unusual sound might be heard.

Luckily, many of the causes of a noisy well pump can be resolved relatively quickly and easily.

But in some cases, you might have no choice but to buy a pump replacement. A professional well contractor can help troubleshoot and resolve the issue if you’re unsure.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

2 thoughts on “Why is My Well Water Pump Making a Loud Banging Noise?”

  1. Avatar for Jennifer Byrd
    Victoria Addington

    I looked into the water pump my mother indicated because she had been hearing banging noises from it. It’s a good thing you pointed out that the pump might be short cycling because of a blocked water supply. I’ll make sure to let her know about this and advise her to look into experts who can assist her in fixing it. I appreciate you sharing!

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