I took a picture of the remains of my failed valve. Looks to me like the O-ring failed, allowing water to slip by. Yes, my town has VERY hard water.

Cutaway of my failed valve

I would not trust them in an RV application. I also wouldn't put copper in an RV application. Too much vibration, thinking soft (non metallic) tubing and clamps would be best in most cases.

Our plumber would have said the same, as long as things are typical. Certain installations require atypical solutions. I am fine with it as long as they cleared it with me prior to installing. Ultimately, it is my choice to accept or reject the proposed solution.

In the case of our butt connectors that a plumber installed, the soldered fittings would not seal and he had two days into the last few fittings.

In this case the fitting was separating at the threaded portion. Will grab some pics later if I get a chance.

PVC? PEX is a different plastic than PVC.

To be fair, this fitting was at least 5 years old, possibly older.

The plumber that installed our water heater had a heck of a time with getting sweat joints to seal up in one section, so ended up having to use them and was very apologetic about it. Those are just butt connectors and are still fine.

I am not saying Sharkbite are bad, just want folks to be aware tgat they may want to keep an eye on them.

Seeing as the metal broke, I am guessing it was a flaw in the casting. I do not think it was the O-ring but also had a heck of a time getting the one end off the pipe. Rather than wreck or scar the pipe I ended up sawing off the fitting. Will be replacing with a sweat fitting as I have never had one of those leak.

I know a lot of folks love PEX, but I am not yet sold on it. So far, the fewer joints argument and the cost argument are strong but the fact that it is a petroleum based product and that it can not be recycled, except into lower graded products, leaves me on the fence about it. That said, I do have a couple PEX lines in our home and will keep an open mind about it for now.