Appliances like dishwashers and washing machines can shut the water off quickly. So if you have high water pressure, and the water stops suddenly, that can cause the banging noise, or water hammer. First, have a licensed plumber check your water pressure.
Q: After saving for years, we finally completed our new kitchen. We love the layout and state-of-the art plumbing fixtures. The only issue we need to resolve is that when the dishwasher cycles, we get a banging noise in our water pipes. The appliance guy says the dishwasher is fine, and we need to check our plumbing. Strangely, if we open the kitchen faucet while the dishwasher runs, there is no banging. Where do we start, and what can be causing the noise? -- Holly, Alabama.
A: This could be a case of what's called "water hammer," and it's very common in houses that have high water pressure. In fact, your question may hold the answer to your problem.
You said that if the kitchen faucet is on, there's no banging noise with the running dishwasher. Well, the open faucet may be acting as a pressure release for the plumbing system.
Appliances like dishwashers and washing machines can shut the water off quickly. So if you have high water pressure, and the water stops suddenly, that can cause the banging noise, or water hammer.
First, have a licensed plumber check your water pressure. If your water pressure is over 80psi, your plumber may suggest several solutions. Usually, he can install a pressure-reducing valve to lower the water pressure, and install a water-hammer-arrester control.
Water-hammer controls act like small shock absorbers for a plumbing system and can quiet the noise as well.
Bottom line: In this case, a good plumber won't give you a lot of "bang" for your buck!
Ed Del Grande, master contractor/plumber and LEED green associate, is the author of "Ed Del Grande's House Call" and host of TV shows on Scripps Networks and HGTVPro.com. Visit eddelgrande.com or write email@example.com.