Bang! Pop! Schreeeeeeechhh!

Is that what your pipes sound like? Then you likely have a water hammer. While many plumbing issues exist, water hammers can likely lead to severe damage and costly repairs. The noise isn’t only disrupting, it’s a sign of excess strain on your pipes that should be dealt with sooner rather than later.

Why Does Water Hammer Happen?

The banging sounds in your pipes happen because of hydraulic shock. A shut-off valve serving your high-pressure water line closes abruptly, causing fast-moving fluid to slam up against it. The result is a shock wave that affects the entire pipeline.

Pump failure can trigger water hammers as well; a sudden failure causes fast changes in fluid velocity. Downstream of the failure, fluid continues to flow, creating a vacuum.

Water hammer often occurs with washing machines. When the machine fills up, water quickly rushes in from the pipes until the drum is filled to capacity. This triggers the washer valve to close while fast-moving water is still flowing through the pipe. Due to an intense surge in pressure, the pipes physically move and bump up against other pipes, wall framing, and other building materials.

How Does Water Hammer Damage My Plumbing?

Water is an incompressible fluid. It, therefore, generates a shock wave when forced to stop suddenly. It takes less than half a second for a plumbing valve to close, creating a pressure spike that can be >10x the normal operating pressure.

This can result in a sudden failure or cumulative damage that deteriorates your plumbing over weeks, months, or even years. If left unchecked, the water hammer can:

  • Damage valves, pumps, pressure gauges, flow meters, gaskets, and expansion joints, and welded joints as well as the walls of pipes.
  • Strain piping support systems to the point they become weak and unable to maintain the integrity of your plumbing.
  • Cause leaks due to damage, joints, fittings, and connections; these often start slow and increase gradually in intensity.
  • Lead to pipe rupture and complete pipeline failure, which often damages other systems, requiring expensive repairs to plumbing, electrical equipment, and your property.
  • Increase the health and safety risks to building occupants, employees, and maintenance personnel, who can face slips, falls, or electrocution.
  • Cause damage to or a loss of product in food and beverage, manufacturing, pharmaceutical, and other operations.

Can Water Hammer Be Avoided?

To prevent water hammers, plumbing systems can be properly designed in the first place. For example, designers can lower fluid velocity using pipe sizing charts and accounting for the application. Shorter branch pipes, shorter straight pipes, elbows and expansion loops, and a looped configuration for primary pipes can reduce water velocity and pressure.

Other ways to avoid water hammer include:

  • Choose a different type of check valve: Gravity-dependent valves like swing, piston style, and tilting disc valves create pressure waves. Spring-assisted check valves move into position before the flow reverses, preventing conditions that trigger water hammers.
  • Adding air chambers to your plumbing: Short segments of pipe feature an air-filled chamber that acts as a shock absorber in your plumbing system. When water suddenly changes direction, the chamber allows it to expand, reducing the magnitude of shock.
  • Reduce pressure at the water meter: Use a pressure-reducing valve to adjust flow at the meter. If you don’t have one, ask your local utility to check your water pressure. Municipalities typically check the water pressure and make adjustments for free.
  • Secure your water supply lines: Water lines are fastened to wooden joists with U-shaped pipe straps during construction. If there are too few or missing straps or they’re not tight enough, the pipes may move and make noise. To stop this, install additional pipe straps or tighten loose ones with a screwdriver.
  • Install a water hammer arrestor: This device features an air-filled cylinder to reduce water pressure. It has screw-type connectors that make installation easy. The unit installs between the water supply line and shut-off valve; ideally, install one for the hot-water supply line and one for the cold-water line.

Contact Express Plumbing Services

We specialize in all types of plumbing repair in the Treasure Valley. If you are experiencing water hammers, our piping experts can evaluate the system, address high water pressure, fix leaks, or install replacement PVC, PEX, and copper piping. Call today to learn more or schedule a visit.

Brad Jordan

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