What Does It Mean When You Hear A Loud Bang Whenever Your Well Pump Shuts Off?

Posted on: 26 September 2019

Do you hear a loud bang whenever your well pump shuts off? This is a fairly common problem, and it's an annoying one — it can wake you up at night when the pump cycles and can sometimes be loud enough that your neighbors can hear it.

Thankfully, this problem is easy to diagnose. It's almost always caused by a faulty check valve. When the check valve on your well pump stops working, it allows water to reverse direction in your pipes once the well pump shuts off. This creates a shockwave that travels through your pipes and causes the loud banging sound. To learn more about this problem and how you can stop it from happening, read on.

What Is a Check Valve?

When the well pump shuts off, the water in the pressure tank naturally wants to reverse flow and go back down into the well. Since the water in the tank is under high pressure, it does this quite forcefully.

The purpose of the check valve on the well pump is to stop water from reversing direction. It closes immediately once the pump shuts off, preventing trapping water near the tank and preventing it from flowing back down into the well.

Why Does Water Hammer Occur?

When the flow of water is reversed within your plumbing pipes, it creates a hydraulic shock that's commonly referred to as a water hammer. The force of the sudden reversal causes the pipes to vibrate, and these vibrations travel through the pipes and cause them to move around. The loud sound you hear from a water hammer event occurs when pipes slam against other pipes or against wall studs.

Metal plumbing pipes are more susceptible to water hammer events than plastic ones since the metal transmits vibrations more easily. However, water hammer can still occur in plastic pipes.

Can Water Hammer Cause Problems?

If the problem isn't addressed, water hammer can eventually cause damage to your home's plumbing. The vibrations can loosen pipe joints and cause them to come apart, and pipes that slam into each other or against the walls can become damaged. Both can cause leaks in your home's plumbing.

Another problem that can occur is backspin. When water reverses, it causes the well pump to run backwards for a moment. Well pumps aren't designed to do this, so backspin can place a significant amount of wear on the pump and cause it to fail faster.

Why Do Check Valves Wear Out?

Most check valves are spring-loaded, and the spring is placed under a considerable amount of stress whenever the check valve closes. Eventually, the spring simply wears out and breaks. Once this happens, the check valve won't function. Whenever the well pump shuts off, water reverses direction and causes a water hammer.

How Do You Fix a Faulty Check Valve?

Check valves are inexpensive, but replacing them is a complex job since it's located on the well pump itself. You'll need to call a water well system repair service to pull the pump out of your well and then replace the check valve. While the pump is out of your well, the technician will have a chance to inspect it for any problems that may have been caused by a malfunctioning check valve.

If your well is waking you up at night with its loud banging noises, call a water well system repair service to pull the pump and inspect the check valve. You'll be able to stop water hammer and prevent damage to your home's plumbing.