When deciding which fittings to use for PEX piping there are a wide variety of products and tools available, as well as a variety of variables to consider, including costs, safety and ease of installation. If you don't do the research you could end up with major headaches, like getting sued due to groundwater contamination or a leaky system.

"There are so many choices for PEX fittings," said Marisa Chandley, senior marketing manager for Vanguard Plumbing, a company that sells PEX pipe and fittings. "What I would focus on is insuring that the fittings you purchase have an ASTM standard and are marked and certified by a third party agency like UL or NSF, or some other third party testing and listing agency."

Cheap brass fittings are being imported from China and Korea without a third party listing, Chandley said. They look an awful lot like fittings that do meet high standards. "Without that little mark on the side that says UL or NSF, you wouldn't know the difference."

If it is third-party certified, it is tested for health standards to make sure it's not leaching any unhealthy material into the groundwater. "Obviously there is a contamination concern if it is not listed or tested," Chandley said. Because of problems with polybutylene, PEX's predecessor, all plastic fittings are listed. "Primarily, because there is a fear in the marketplace over plastic not performing, [plumbers] really want to cover themselves when they buy a plastic fitting," Chandley said.

For standard applications, Chandley recommends brass fittings. "But in areas where water is very acidic or you have contamination concerns, plastic fittings are definitely preferable," she added. In hot soils or acidic water conditions, brass tends to corrode and can cause a failure over time. "There are times when you would definitely want to use a brass fitting. For example, when you might be exposed to certain chemical agents at the application. Plastic does not react well--depending upon...