If I don't notice water hammer, do I still need an arrester? I am replacing my home's copper pipes with cpvc. My existing pipes have air chambers, but they are most likely not working because it's been proven air chambers fill with water rather quickly. Since I don't see or hear water hammer, I am reluctant to install store-bought water hammer arresters. I may not need them because my water pressure is on the low side...40 psi. However, like most people, I am replacing my copper pipe with the same size cpvc pipe. However, the inside diameter of 3/4" cpvc is about 14% less than 3/4" copper pipe, so my water velocity should increase. I could use a "wait and see approach"...install the new pipe without the arresters and see if I notice any water hammer. If no hammer, than I am good. If hammer, install the arresters. So, my question boils down to: If you don't notice water hammer, can your plumbing system still be damaged over the years? Thank you.

By the way, the cpvc manufacturers say their pipe will absorb the water hammer so you probably don't need arresters. The arrester manufacturers say you still need arresters even if cpvc makes the hammer noise go away because the shock waves will still damage your plumbing.

All I can tell you is that I have NEVER installed water hammer arrestors and none of my customers have ever mentioned having water hammer. Water hammer is a function of high velocity and fast closing faucets.

What's wrong with the copper? Why CPVC?

I wish I knew why copper doesn't last around here; South Florida. There are many theories: Electrolysis from grounding home electrical system to pipe, excess chlorination from city, minerals in water, etc.

South Florida was covered by the ocean years ago, so we have coral rock, limestone, etc. in the ground. You are lucky if you have more than 1 inch of topsoil. Digging a trench or planting a tree is a major job in itself. The water is very hard and alkaline. I believe the pH is around 8. I ordered some test strips online so I can confirm the pH.

Schedule M copper pipe last less than 10 years before developing pin holes. This is the third set of pipes I am going to install. Several local plumbers told me they don't install copper anymore around here.