Flexible water lines, to some the greatest thing since “Romex” wire for houses. No longer does a person need to fight with rigid pipe when they are plumbing a residence. The product has been around for many years in Europe, and the manufactured home industry has been using it for a number of years in the US. Its claim is that it is easy to work with, fewer leaks and it is quiet. Having spent time working with copper plumbing and cast and plastic waste/vent lines in the past, the flexibility and ease of installation is obvious to us. Not having to connect lengths of pipe every time we have to join two lengths or have to make a corner will reduce the potential for leaks. It is the “quiet” claim we have concerns with.
Having spent a lot of time in two residents that use PEX, it is not a silent solution. Yes it has fewer fitting connections and therefore there is less turbulence as water flows through it, however it is still loud. When installed per the manufacturer recommendations, we still have flow noise, and the water hammer at the end of a long run actually seems louder, given how short the run really is. Our recommendation – when you use PEX, continue to isolate the lines and use the same acoustical details that we have developed over the years for copper.