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A Guide to Water Hammers

A “Water hammer” is a plumbing sound many homeowners come across at one point or another. Water hammers sound like a loud thumping or pounding sound your pipes make whenever water flows through them.

Water hammers happen when water suddenly changes direction inside of a pipe, like when a faucet is turned on then off. The momentum involved can create waves of pressure that generate the telltale sound, along with other potential problems. Here’s everything you should know about water hammers–including how to stop them.

Okay, so what is water hammer?

Like we said above, water hammers happen when water inside of a pipe quickly switches direction. When a pipe suddenly closes at its outlet while water is running, it forces the mass of water still moving inside to stop very quickly. The force of the water coming to an abrupt stop leads to the shock wave and loud sound. There are a number of problems that accompany water hammers other the annoying sounds, too.

Unsurprisingly, when that water runs into pipe walls at high speeds, it can hurt the pipe or its connective joints. This damage could cause leaks or even burst pipes. Left unchecked, water hammers could even loosen your pipes or put too much pressure on your water main. You definitely don’t want your water main to burst.

How do I fix it?

There are a number of different solutions to water hammers, depending on your needs and preferences. You could…

Invest in some water hammer arrestors.

Water hammer arrestors are devices that feature cylinders filled with air. These air pockets absorb the jolt of a sudden water pressure increases. They’re easy to install, since they just screw onto existing pipes. Water hammer arrestors basically just give a little extra cushioning power to the existing air chambers. If you’re not already familiar with home plumbing, we recommend calling a plumber in to install these for you.

Drain your plumbing system to clear waterlogged air chambers.

If you’re hearing water hammers, it’s probably because the air chambers in your pipes are waterlogged. Pipe air chambers are supposed to absorb the shock that comes from moving water. They do that by providing an empty place for that shock to dissipate. When your air chambers fill with water, however, they can’t accomplish their job. Instead, the full shock of the water impact hits your pipes, and you get a water hammer.

To drain the air chambers, turn off your water and open the highest and lowest faucets in your home. Water will drain out and the air chambers will refill with air. When the air chambers clear out, they’ll be able to absorb the pressure that causes water hammers again.

Make sure your water pressure is at a safe setting.

Water hammers sometimes happen because your water is too pressurized. It’s shooting through the pipes too hard, and so the shockwave it produces is too large. 

Contact the municipality that controls your local water system to check on your home’s water pressure. Most municipalities will check on your pressure for free and reduce it if necessary.

Afraid a water hammer has damaged your pipes? Don’t panic! Just give Ben Franklin Plumbing a call anytime. We’ll fix your pipes up like new.