I want to run a new water line to a bathroom(recently added on to our home's main floor) and the existing plumbing is copper piping. Can I use plastic piping for the new water line, or does it have to remain copper all the way to the fixture?
Howard S. ~ Carmel, NY
When you say "plastic piping" Howard, I'm going to assume that you are referring to PEX tubing, and not PVC pipe. I don't recommend using PVC piping for residential water supply lines, because PVC can crack far too easily for my comfort level (although CPVC piping is widely used for home plumbing). On the other hand, I love PEX piping, not only for its durability and flexibility, but because it is also pretty straightforward to work with.
Adding a new water line to your house's existing copper plumbing using Pex piping is no big deal at all, and there are several plumbing fittings available to create the water-tight joint needed between the two different types of pipe. If the plumbing connection is going to remain accessible, then you should also install a shut off valve at the junction so that you can quickly shut off the water supply to the new bathroom when the need arises.
There are several different brands of PEX tubing available, and I usually recommend that homeowners choose a brand that is readily available at their local plumbing supply warehouse. Most PEX fittings are connected to the tubing using a crimping tool and some style of metal banding. One type of PEX fitting that does not require the use of a crimping tool is called a Shark Bite. Shark Bite fittings just slide onto the tubing, locking themselves into place, which makes for a quick and easy connection. Shark Bites can also be used on copper pipe, so you could use one to connect your new bathroom PEX plumbing to the existing copper water supply. The fittings cost between $5-$10 a piece, so although plumbing a whole house with Shark Bites might be expensive, they are well worth the money for small plumbing projects like yours.
If you plan on completing the work yourself, then you should check your local building codes to make sure that all your plumbing work and material are code compliant. If you are unsure of how to install the new water line to your bathroom, then you should consult a contractor or licensed plumber in the Carmel area who has thoroughly inspected your house. Good luck with your project, and I hope you enjoy the new bathroom!