water hammer

What is Water Hammer?

Have you ever heard a loud thump or bang after your dishwasher or washing machine fills up and starts the cycle? What about when your toilet tank becomes full and stops filling? The loud noise you are hearing is called “water hammer”. Sounds appropriate, doesn’t it? 

What is water hammer?

This noise can be quite a shock because it sounds like someone is literally banging on your pipes or walls with a hammer. Speaking of shock, water hammer is actually caused by a shockwave of energy that simply has nowhere else to go. The technical name for water hammer is actually a hydraulic shock. Water hammer occurs when water is moving through your system at a high velocity, about seven to ten feet per second, and the valve shuts quickly causing the water to stop abruptly. That’s when you hear that loud bang because the shockwave of energy has nowhere to go so the energy is released as noise and vibrates back through the pipe. To visualize this, think of it like a car going down the street and running into something. 

Can water hammer cause any damage?

If water hammer is not fixed, it can cause issues within your plumbing system. The longer water hammer occurs, the more severe these problems can be. Therefore, it’s important to mitigate your risk of serious issues before it is too late. The most serious issue that can occur is your pipe bursting. The longer water hammer goes on, the weaker your pipes get. This is especially true for plastic pipes and pipes that have become brittle due to chemicals in the water when a chlorination system is used. When you have a burst pipe, fixing the pipe is not the only cost you will incur. According to Restoration Local, the national average of water damage restoration is $2,700. As you can see, it can be quite costly so it’s advantageous to not wait until this happens.

Another problem you may have from water hammer that is not related to your system is that it can be quite an annoyance. The noise can be so loud that when you get up to use the bathroom at night, the thumping can wake other people in the house up. Don’t let your plumbing be the reason for sleep disturbances – get it fixed!

How do I fix water hammer?

As stated previously, water hammer is mainly caused by having no solution for releasing the energy and by having high water pressure. You can release the energy in several ways. The most common way is by installing an air arrestor. This is a device that goes in your pipe acting like a bladder that has air on one side and water on the other. This bladder essentially provides a cushion of air. That way, when the vibration comes back through the line, it’s absorbed by the air because air is compressible, where water is not.

Another option when fixing water hammer is to change out the valve to one that does not close as quickly. This not only slows the water down but it prevents the water from stopping abruptly which then alleviates the hammering sound.

Some things that often trigger water hammer are buying a new dishwasher, washing machine or other appliances that use plumbing. Many of these appliances, such as washing machines, can have an air chamber added that screws onto the valves to prevent water hammer. 

While there are multiple ways to fix water hammer, there is really no way to prevent it. If you have been hearing the thumping noise, we suggest that you call a licensed plumber to provide the best solution for you.