Copper vs. CPVC

There are no simple answers as to whether to use copper or plastic (CPVC) pipe for delivering a home's drinking water. But doing some homework will help contractors be ready to offer the best options for a customer.

"The answer varies from home to home and site to site," says home designer and one-time general contractor Jozef Tara, owner of West Bath, Maine-based Tara Design Inc. "So many factors come into play that I don't feel there's one set answer."

Water Types and Cost
In many areas, particularly those without municipal waters sources, the acidity of the home's water may be a decisive factor in choosing CPVC (chlorinated polyvinyl chloride) piping. Highly acidic water can break down copper pipes over time and promote green staining in fixtures almost as soon as the water's turned on, Tara says. Although acidity can be dealt with by passive water filters, they must be recharged every year or so. Tara says many homeowners might opt instead for acid-indifferent CPVC piping.

CPVC piping became accepted among home builders in the northeast about 25 years ago, although today it still accounts for only about 15 to 20 percent of new plumbing installations while copper accounts for the lion's share of the remaining 80 to 85 percent of the market. Copper began replacing labor-intensive iron pipe installations about 45 years ago.

Until recently, the cost of CPVC pipe and copper pipe were close, with a small advantage going to CPVC. Copper prices, however, have skyrocketed over the last year or so and CPVC now has a marked advantage over copper—although that may soon disappear if oil prices stay high and push up the price of petroleum-based products like CPVC pipe. So over the long term, Tara sees the cost benefits between copper and CPVC as minimal.

Installation Concerns
Plumbing contractor Glenn Tourgee of Marlboro, N.H.-based GT Plumbing and Heating, says he sees both health concerns and installation problems with CPVC. "Some customers look at the pipe and the solvents we have to use (for CPVC) and say they don't want it because they don't want that stuff in their drinking water."

However, customers concerned about problems with the chemicals used in making or working with CPVC pipe are probably misguided. The Ann Arbor, Mich.-based National Sanitation Foundation (NSF), periodically checks U.S.-manufactured pipe for any objectionable trace chemicals that could get into the drinking water. If there are no trace chemicals, the pipe is certified by NSF.

"Any CPVC pipe used for domestic water systems ... must be NSF-certified to be used in the system," says Judy Makowski, a spokeswoman for Noveon Inc., one of the biggest domestic manufacturers of CPVC pipe. She also notes studies have shown CPVC pipe has a better track record than copper in the growth of "biofilm" on the pipe's interior walls.

Tourgee also finds CPVC pipe problematic on repair jobs. "Nobody wants to wait the full 24 hours," he says, referring to the time period during which CPVC pipe should not be pressurized to allow the pipe adhesive to set up properly. He notes many customers will start using a repaired system long before the 24-hour time period is up. Copper can be used within minutes of a repair.

Iron Pipe and the DIY Factor
However, CPVC pipe is frequently preferred over copper pipe when making repairs to an old-fashioned iron pipe water system. The plastic pipe will not corrode when in contact with iron pipe. Depending on the trace chemicals found in local water supplies, copper pipe usually will corrode badly when used in direct contact with iron pipe. CPVC is one of the few inexpensive solutions to this problem.

Tourgee and Tara both agreed CPVC pipe is easy to work with and favored by do-it-yourself plumbers, which makes some prospective homeowners want to specify the material. A customer who is CPVC-inspired may want to check out a local Lowe's do-it-yourself seminar to be sure he follows all codes and proper procedures. Click here to find a local clinic.