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Fix a Loud Water Hammer

  • Transcript

    LESLIE: Jim in California has the very annoying sound of a water hammer. What can we help you with?

    JIM: Well, I listened to your show about a month ago and I just got in the tail end of the water hammer problem …

    TOM: OK.

    JIM: … underneath a kitchen sink. And you were describing two types of devices that can be bought. You said one was about the size of an inhaler and don’t get that; that’s a toy. That there was a bigger one about the size of a baseball that actually …

    TOM: Yeah, about the size of a softball. It’s called a water hammer arrestor.

    JIM: Yeah.

    TOM: And it’s like a little shock absorber that gets installed by a pro into the line. And essentially, what causes water hammer – for those that are not familiar with it – is as you run water through a faucet in your home that water essentially builds up a centrifugal force because water’s very heavy. It weighs about eight pounds per gallon. And when you turn the faucet off all of that centrifugal force wants to keep moving forward. And if the pipe is a little loose it will bang and that’s what we call water hammer. One way to deal with that is to install water hammer arrestors. That will soften it.

    The other thing that can be done if you have access to the pipes is simply to secure them. Many times I’ve found water hammer problems that could easily be solved just by putting additional brackets on piping across crawlspace ceilings where pipes were hung or across floor joists in the basement. If you have access to those pipes you can tighten them up so they don’t shift and shake as much. But if you can’t get to it you can always put in a water hammer arrestor, Jim, and that will solve the problem.

    JIM: OK. I’ve been to my local home centers and hardware stores and they’ve heard of them but they don’t have them.

    TOM: No, you need to go to a plumbing supply house. And Jim, it’s not something you can install yourself. You’ll probably need a plumber to do that.

    JIM: OK. Well we really started noticing it. We’ve lived in the house for quite a while and had no problem. And I recently installed a beautiful, high-tech dishwasher. Paid a fortune for it but you can’t even hear the thing run. That’s beautiful. But I guess it has some pretty high-tech solenoids in there when it shuts off the water; when it goes through its cycles. And you know, it’s just – it’s not like when you gently turn off a water tap.

    TOM: Now the good news is you have a quiet dishwasher. The bad news is you have loud plumbing pipes now. (chuckling)

    JIM: Great.

    TOM: So you can – they were probably always loud but now you can hear them because the dishwasher’s so quiet.

    Jim, thanks so much for calling us at 888-MONEY-PIT.

    JIM: OK, thank you.

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