DIY Tips From the Warner Service Blog

What A Hammering Noise Means For Your Drainage System

Posted by Warner Service on Dec 1, 2017 9:00:00 AM

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Every homeowner gets nervous when they hear a loud bang or pop in their home. After that initial sound, all you can see are dollar signs. 

But what if the solution to the sound wasn't as costly as you thought? If you hear a hammering noise in your home's pipes, here's Warner Service's advice on what you should consider doing: 

Water Hammers. When a stream of water travels down the narrow pipes of your home's drainage system, it's traveling at a very fast pace. As it finds a closed valve, which was once a free-flowing escape from pipe to pipe, the abrupt stop creates a loud thud that can be heard throughout your entire home. 

The abrupt stop is due to an air chamber. Air chambers are responsible for cushioning water to prevent it from slamming against the pipe, which is capable of damaging drainage joints and connections. Most air chambers exist in only critical locations, like the dishwasher and washing machine, where electric valves close rapidly.

However, in some homes, air chambers exist in every location where water is turned on and off, including every toilet and sink. 

The hammering action against the air chamber that resulted in the loud thud is called a water hammer. To fix it, you need to replenish the air in every air chamber -- not just the one that's closed. 

However, you can't inspect air chambers on your own, but you can (and should) perform the following plumbing maintenance check-up with every faint noise you hear in the pipes: 

  1. Shut off the main water supply valve to your home.
  2. Open the faucet that's located near the highest point in your house, which is usually on the second floor or in the attic.
  3. Turn on the faucet that's located near the lowest point in your house, which is usually on the first floor or in the basement.
  4. Turn off the lowest faucet and reopen the main water supply valve when the water is completed drained from the pipes. 

Loose Mounting Straps. Occasionally, water hammers occur from loose mounting straps on a pipe. These straps consist of metal plumber's tape (though never galvanized on copper pipes due to the potential of electrolysis and subsequent water leaks) or vinyl-coated nail-in hooks and hangers that attach pipes to your home's framing.

A loose strap allows it to repeatedly snap against the framing as the water is turned on and off throughout your home. To fix this plumbing problem, call a local professional to check all accessible pipes for proper and tight connections. 

Too-High Water Pressure. A hammering noise doesn't always come from an actual water hammer. On occasion, the loud thud can come from excessively high water pressure. 

To fix this plumbing problem, adjust the water pressure with a water pressure regulator (which comes built in near the main water supply valve of most new construction homes) or pressure-reducing valve.

If you don't have a built-in regulator, contact a local professional to install one to avoid damage to dishwashers, icemakers, washing machines, and other water-supplied appliances. 

You should also regularly test the water pressure using a water-pressure gauge that can screw onto a hose bib. Normal water pressure runs around 30 to 35 PSI and should never exceed 50 PSI.

Remember: A hammering noise isn't the only sound that faulty pipes make when there's a plumbing problem. Click here for more details on what you should be listening for in your home's drainage anatomy. 

You can also download Warner Service's troubleshooting checklist by clicking on the button below:

Topics: Maintenance, Plumbing, plumbing tips, water use, do it yourself