Old rusty pipe with leak and water spraying out from water hammer damage

Water Hammering: How To Fix Your Noisy Pipes

Have you ever heard a loud bang or repetitive banging coming from your water pipes? Or maybe it sounded more like clanging, shuddering, or knocking. What you’re hearing is what plumbers call water hammer (or water hammering) because it sounds like someone is literally hitting your pipes with a hammer.

Why Do My Water Pipes Hammer?

Put simply, water hammer can occur when the water flow from a water-using appliance is suddenly shut off. Common examples of water-using appliances include dishwashers, toilets, faucets, water heaters, waching machines, showers, and toilets.

But there’s more to it. When a water valve is suddenly closed, the water can no longer flow in the direction it was moving. The water has to suddenly stop and change its direction. The sudden stop means that the water is slamming into a closed valve at up to 8x normal water pressure. This creates and sends a shockwave (also called a hydraulic surge) through your pipe. It is this shockwave that produces the loud bang you hear.

Of course, this can happen in any pipe where valves are used to control the flow of water. Even the flow of steam (which is just water in the form of a gas) can cause water hammer if a valve is quickly shut. In addition, it doesn’t have to be water or steam in your pipe that causes water hammer. Commercial property and maintenance managers are always on the lookout for pipe hammering that stems from oil and gas pipes.

Will Water Hammer Damage My Pipes?

If water hammer simply caused a loud banging noise, it would be relatively easy to ignore (that is, after the fright from your jump-scare wears off). Unfortunately, the shockwave and water pressure can cause major damage to your pipes, joints, and valves. And much more. A weakened pipe will result in a number of problems, including:

  • Water Pipe Leaks — the most common damage occurs from a small or large leak that has resulted from a weakened joint or valve; these leaks often begin slowly and gradually increase over time
  • Ruptured or Burst Pipes — water pipes are made of different materials, each with their own tolerances for temperature and pressure changes; if ruptured, the water damage can be severe and expensive
  • Water Damage to Your Property — water damage from a ruptured or burst indoor pipe can cause major property damage that leads to large-loss claims
  • Damaged Gauges & Sensors – in the home, the accuracy of water gauges can be affected, as well as damage to the water sensor itself
  • Damage to Water Flow Systems — water pressure back-up can cause damage to pumps and support systems such as pipe walls, pipe hangers, and supports
  • Environmental Issues – leaking water, especially behind walls, can create a situation where toxic mold can grow and cause severe breathing issues

If you have water hammer or experience any of the above issues, contact your plumber immediately to asses the health of your pipes, joints, and valves. Your plumber will also give you options for fixing the problem.

3 Options for How to Fix Your Noisy Pipes

There are a number of ways to fix a water hammer issue. But let’s focus on a couple of DIY (do-it-yourself) methods for resolving (at least temporarily) your problem. These methods can’t guarantee that your problem will go away completely, but they can, at least temporarily, address your immediate situation.

Option 1 – Call Your Local Water Utility

  • Call your local utility. You can find the phone number on your water bill or on the internet.
  • If they can’t walk you through the solution over the phone, they might send someone to to your property to reduce the water pressure at the water meter.

Option 2 – Lower Your Water Pressure

If you’re home is relatively modern or has updated pipes, this is an easy remedy that should work. And you’ll get the satisfaction of doing it yourself without the downside of having to wait (perhaps) days for a utility employee to show up at your door.

  • First, shut off your main water line’s valve — in cold-weather areas, it’s usually located inside within 3-5 feet of your water meter; in warm-weather areas, it can often be found just outside the home near an outside faucet
  • Then open the highest faucet in your home
  • Now drain the water from the lowest faucet (usually located in your basement if you have one, otherwise it will be on the first floor)
  • That’s it. What you’ve just done is add air back into the air chamber that’s part of most modern water pipe systems. It’s likely that this air chamber lacked enough air to act as a shock absorber for your high water pressure. That should be resolved now.
A water shut-off valve can look different to the untrained eye. Here’s one located in a basement.

Option 3 – Install a Water Hammer Arrestor

If the above options don’t work, or if you have an older home, you might need to install a water hammer arrestor — a plumbing device that absorbs the shock caused by high water pressure hitting a suddenly closed valve. Think of it as a shock absorber for your water pressure.

Don’t worry, most arrestors have screw-on connections that will attache between a water supply line and a shut-off valve. However, depending on your situation, you might need to cut into your water pipes to install the arrestor. It’s important that two of these are installed; one for your hot water supply line and one for your cold water supply line. The cost for each is about $15. Here’s a video showing the problem and how to install (the hard way) the water hammer arrestors.

It’s important that two of these are installed. One for your hot water supply line, and one for your cold water supply line. The cost for each is about $15.

Option 4 – Call Your Plumber if You Have Water Hammering

If you need more help, don’t hesitate to contact us or call us at 1-Tom-Plumber (1-866-758-6237). We immediately handle any emergency plumbingdrain cleaning and drain clearing, and water damage problem, including excavation of underground water lines and sewer main lines.

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