Plastic water supply piping (C) Daniel Friedman Copper vs Plastic Pipes in Buildings: Which is Better?

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This article describes the pros and cons of using copper or plastic piping in buildings. We explain the advantages and possible downsides of choosing one or the other (plastic piping or copper piping for water supply or drains).

The question of which is better, copper or plastic piping, copper or PEX, copper or ABS, or copper and PVC or CPVC piping has answers but the results may not be as unambiguous as one imagines. Each piping material & piping connector or fitting system has both its advantages and its concerns.

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PLASTIC vs. COPPER PIPES in BUILDINGS: is one preferable?

Copper, Galvanized iron & Lead piping (C) 2009 Daniel FriedmanMany plumbers prefer to work with copper and, although plastic pipe is less expensive than copper, the fittings are expensive. Some areas do not allow plastic pipes based on environmental concerns.

Some questions have been raised about the chemicals used in the adhesives used to join sections of piping, and the toxic gases given off from plastic piping during a fire.

Polyethylene (PE) and polyvinyl chloride (PVC) are only suitable for waste, underground water service pipes or cold water piping systems.

Our photographs of plastic water supply piping connections just below show a new water main (below left) and building supply pipe being connected to copper piping entering a building (below right) in San Miguel de Allende, Guanajuato, Mexico in 2010.

Plastic water supply piping (C) Daniel Friedman Plastic water supply piping (C) Daniel Friedman

- Adapted with permission from The Home Reference Book

What About the Relative Safety of Copper Piping vs. PEX Piping in Buildings?

Details comparing the concerns, issues, codes, standards, features & questions about possible health concerns where PEX piping is used are found at PEX vs. Copper Piping, safety. Excerpts from that article are below.

Pex vs. Copper Water Supply Piping - which is better?

Reader Question: my daughter is doing extensive renovations on her house and the question has come up whether to use PEX or copper in the plumbing. I did a google search and the informations is conflicted. Do you have knowledge of, and opinions about, this controversy? - Elisha Fisch, New York 2/17/2013


PEX hot and cold water piping installed during new construction (C) Daniel Friedman Eric Galow 2012 2013I have worked with both PEX and Copper piping, though of course

Copper has been around a long time. We recently chose PEX for both water suppy and for a hot water heating line in an addition and so far have been happy with the results.

Our PEX tubing photo at left shows its use in new construction completed in a New York structure in 2012.

You can see the ease of bending radius in these piping runs of both hot (red) and cold (blue) water supply lines.

What follows is an OPINION based on field experience as a builder, renovator & inspector:

PEX water supply piping offers some advantages over copper sweat-fitting piping installation

PEX piping installed in a Haddonfield New Jersey Home (C) Daniel Friedman 2013

Our PEX tubing photo at left illustrates an older PEX piping product installed in a Haddonfield New Jersey Home.

  • Fewer connections, faster installation, lower cost: A PEX piping installation typically requires fewer connections (as the tubing is so flexible). That may mean a reduced risk of a leak -since leaks often occur at connections in piping systems
  • Leak resistance: the PEX tubing is generally inert, so it is rather immune to pinholing problems or corrosion problems experienced by copper piping in some systems where the water chemistry is aggressive or where there is an electrical ground snafu
  • Noise transmission in PEX tubing is less than metal piping, though this is more an issue with drains that supply in most locations.
  • Condensation on the cold water piping exterior is less than on metal cold water supply piping - a factor in some pipe routing locations where dripping condensate can wet an area or cause a mold aggravation.
  • Heat loss in hot water: Similarly, because of the observation that plastic transmits heat less quickly than copper I suspect that there is less heat loss when running hot water for washing or bathing as well as in heating system applications.
  • Freeze damage risk reduction: In an area exposed to freeze risk I think that the risk of burst pipe damage is reduced (probably not eliminated) when plastic piping is ussed
  • Compared with copper piping, a PEX water supply piping installation is easy and fast. Cuts are made with a simple hand tool, and fittings are installed with a different tool. Speed of installation should save on labor and maybe on overall cost; the connectors cost more but you use fewer of them;

PEX Supply Piping Caveats & Health Questions

Pex water piping markings & codes (C) 2013 Daniel Friedman

  • Possible MTBE Contamination associated with PEX water piping
  • Chemax, a citation you provided ( ) cites a 2001 study into odor and taste complaints in new homes with PEX piping. An excerpt from that resource states:

    • In the course the investigation it was discovered that t-butanol and MTBE were showing up in the water. The levels of t-butanol spanned a broad range, but in homes where the water had been stagnant for a period of time the concentrations were as high as 10,000 ppb and greater.

      For comparison, the State of California has an enforceable Maximum Contaminant Level (MCL) on MTBE of 13 ppb, and a non-enforceable Action Level on t-butanol of 12 ppb. ...

      Since the chemicals enter the water via a diffusion process, the concentrations were a function of how long the water was in contact with the tubing. ...

      If you are considering whether to build your home with PEX, you might ask the PEX manufacturer for a written letter that clearly states whether chemicals will be added to the drinking water and if so, which chemicals and to what degree. Note that simply passing NSF Standards does not guarantee that chemicals will not be added to your drinking water
      . [18]

  • In 2013 study of these questions continues. Jia Tang et als reported:on modeling the properties of these plumbing materials where water is chlorinated. [21]

  • U.S. EPA information on MTBE as an unregulated water contaminant is
    at MTBE (methyl-t-butyl ether) in drinking water (an EPA website article at ) This article offers:
    • If you want to get your water tested [for MTBE], call the Safe Drinking Water Hotline (800-426-4791) or visit
      our certified labs page to get the phone number for the office in your state that certifies drinking water laboratories.

      More details are
  • SNAFUS: If the installer is not familiar with the product and uses wrong connectors or doesn't know how to install them expect trouble;
  • Hot plastic water piping may require a few more points of support to avoid sags
  • Connector confusion: Because there is a variety of types of connector systems for PEX it's important that the installer understand the system and that s/he has the right installing tools for the connectors chosen.
  • Individual connector fittings cost more than the functionally equivalent copper sweat fittings such as elbows, unions, and adapters to threaded pipe for connection to some devices.
  • If using plastic piping for heating system applications double check with the supplier that the piping selected is rated for safe use in the operating temperature range for the heating equipment.
  • Piping system failures: I think that the issue cited was with connector problems with PEX was specific and not current
  • Environmental issues about using plastic products have some standing with many people who are concerned about using petroleum products and about producing products that remain a very very long time in the environment if/when in waste form.

    But copper mining does not fail to make its mark on the environment either, so one can make an argument against either material. Copper mining in at least some locations means excavating huge holes in the earth; wastewater from mining operations may poison nearby waterways, and some mining operations may also involve health risks or may exploit workers in other countries.

    In my OPINION an argument about which material is more environmentally sound is plagued with ambiguity and conflicts, as are some cases of litigation.

Bottom line on PEX - 2014: although in more than one form PEX tubing or water piping has been used in Europe since the 1970's and in the U.S. for the last 20 years without [we have not found report of] a study confirming health injury associated with the material, still based on a literature review (citations are at the end of this article) in our OPINION there may be a contamination concern where PEX water supply piping is used.

We will continue to monitor the PEX health and contamination question and will update here. CONTACT US by email to send field reports or to report on new studies.

Copper Water Supply Piping: features, propertis, comparison with plastic supply piping in buildings

We discuss types of copper piping and their intended uses and copper fittings beginning
at COPPER PIPING in buildings.

  • Copper piping is something that I personally love aesthetically
  • Copper supply piping is possibly familiar to more installers
  • Copper pipe fittings & connectors are less confusing than plastic - standard, old, known to old-timers
  • If all of the supply or drain piping in a building are continuous metal, then grounding the piping system increases electrical safety - a toaster dropped into a sink should blow a fuse or trip a breaker. This is a somewhat subtle safety point for which we have opinion, not data.

Copper Supply & Drain Piping Caveats

Condensation on a copper water supply pipe (C) DanieL Friedman
  • Copper piping too is at risk of leaks, even long-standing clandestine in-building-cavity leaks (when the leak is tiny) if each fitting is not installed properly
  • Condensation where cold water supply pipes run through building spaces is common on all pipe materials but occurs more quickly on metal pipes such as the copper cold water supply piping in our photo at left. In some locations the condensation and dripping of water can contribute to a building mold, insect, or other water-related building problem.
  • More than plastic water supply piping, copper piping is more vulnerable to leaks caused by aggressive water chemistry, or by an electrical ground mistake as well as leaks due to galvanic corrosion if piping is mixed with steel in an older home (unless you use proper diaelectric fittings at those joints).

  • More easily than plastic water supply piping, copper pipes can be damaged by vibration (OPINION),

Water supply piping connection: copper to galvanize (C) Daniel Friedman

  • An amateur installation during copper fitting sweating (soldering) sometimes pushes too much copper into the joint leading to a very hard-to-find flow restriction.
  • Lead in solder used to join copper water supply piping in older buildings can present a lead poisoning health hazard that varies by the extent of lead solder used, how the joints were soldered (did the installer push blobs of solder into the pipe interior), and the chemistry of water flowing through the pipes. Lead hazards associated with water piping are discussed in detail

    Our photo (left) shows how a homeowner coped with a leak at a soldered (sweated) copper water supply pipe elbow that was difficult to reach for repair.

We discuss types of copper piping and their intended uses and copper fittings beginning
at COPPER PIPING in buildings.

In sum, I don't believe there is a single "right" answer, and each material has some advantages and features that may make it fit a particular installation best. But when I ask my buddy Eric Galow, who is a full time builder, he's a PEX man all the way.


Continue reading at PLASTIC PIPE LEAK CAUSES or select a topic from the More Reading links shown below.

Or see LEAK CAUSES in WATER PIPING for a discussion of the causes of leaks in copper or other metal water pipes

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PLASTIC vs. COPPER PIPES in BUILDINGS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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