Water Hammer Arrestor is the Solution to Banging Pipes

LESLIE: Bob in California is on the line and dealing with some plumbing issues. Tell us what’s going on.

BOB: It is in regards to the water hammer that you get in the plumbing normally. I would say it’s either in the walls but mostly in the ceilings.

TOM: Right.

BOB: And what I understood is – and correct me if I’m wrong – is they run the plumbing in the attic and then they’ll run an extension up a foot or so that just goes up and deads (ph). And it’s to carry a volume of air, so instead of working as a hammer when you turn the water on and off and it hits hard, it uses that air.

TOM: That’s true. That is a way to create a water-hammer arrestor with air in the pipe. That’s sort of the old-fashioned way to do it. The high-tech way is with these sort of small diaphragms that are sort of stretched across the pipe with compressed air on one side, that can actually be adjusted depending on the bang. And the rubber expands into the chamber and then pulls back again. So either is a viable option.

BOB: Ah, I never heard of the other one. But what my question was, being old-fashioned – and my question is: about how often would you put them and how tall? And would they be larger, such as like a hydraulic ram would be or would they just be the normal-size pipe? And I would think, as a preventive measure, you’d do that. The reason I ask is just recently, they changed the plumbing in the attic in the apartment and it developed a water hammer when they changed it.

TOM: So, the answer is they’re usually not very tall, the times that I’ve seen them. But today, I would use a water-hammer arrestor. So just look that up at the plumbing supply house – a water-hammer arrestor – and have your plumber install one of those on each line and that should deal with it permanently.

BOB: I appreciate it. I just thought maybe there was a rule of thumb on how often and how tall that extender was.

TOM: Yeah, you can do that but that’s the hard way. I would use the water-hammer arrestor and that will take care of it the easy way.

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