Howdy. I live in a condo, 8 units, and top/bottom pair share water line relationship. Both pipes run thru my (downstairs) closet wall. Our whole building fought the fog-horn and banging issue with pressure-reducing valve replacements all around in August 2001.

About 9 months later, banging started up again. I had the original plumbers come out and check the whole building. They couldn't "recreate" the noise. Since my PRV was still under warranty, they replaced it.

Less than 6 months later (less than 1&1/2 years from original installation), the machine-gun-fire noise is back in my wall. It started as an occasional noise maybe once a week but has increased now this week to spurts every 5-15 minutes.

Putting my hand inside the wall and on neighbor's pipe reveals her pipe to be the banging one. There isn't room to strap it but there's almost no play in it anyway. (Btw, when it bangs, pipe is often warm to the touch. Not sure how that's possible when her water heater is upstairs...)

Do PRVs die so soon? It's running ~$300 each to replace these things. What is the normal replacement cycle? Is there a top quality brand of PRV that should last longer? Should we both replace the PRVs to be certain we take care of the problem?

And, lastly, have we done any pipe damage by letting the banging go on so long?

Thanks.

PS. No other neighbor-pairs in the building hear banging.

Maybe the banging is her toilet fill valve. That is the most common cause of that noise.

Watts 25AUB's are the good ones, but nothing's infallible and I have had the occasional bad one here and there over the years. Good luck.

Thanks. Two good suggestions. The banging can happen even if she's not home. Would the toilet fill valve be activated periodically even when the toilet is not in use? Also, the only peace and quiet I've had has been when she uses the big water shut-off handle and cuts off all the water to her apartment. Does that information help?

If her flapper in the toilet is seeping water out of the tank, the fill valve will come on very slowly to fill the tank. Some fill valves handle this ok, but I just had one a couple of weeks ago that howled and banged like crazy. Sounded like she had demons in her house. A $4 dollar flapper fixed her problem.

Well, we did the toilet test and the flapper is not leaking... and it's not the fill valve.

Neighbor's pipe is the one that bangs and shakes. She was gone all weekend and it would bang one day, almost every 2 minutes at times, while another day it didn't make a noise at all. Nobody was up there using any water or flushing the toilet during that time.

Our intention is to replace the PRVs on both pipes. My pipe isn't banging anymore after my PRV replacement at the 1 year mark (8/01). But if we got a bad batch at our mass-installation in Aug 2000 then I guess it's not too weird for hers to go now.

My big dilemma is whether to replace mine (at ~$300) if my pipe isn't banging. What if the one I have now works and the new one is busted?!

Any opinions on risk/reward here?