In a nutshell, domestic water piping supplies water to the water heater and to all fixtures in a home. There are many materials used for domestic water piping. Understanding Domestic Water PipingToday, the most common are PEX tubing, CPVC, and copper. Each type of materials has its own individual pros and cons. In the past, galvanized steel was among the materials used in older homes, but it and others are not approved under the 2009 International Building Code.

The following are some details about the most common types of domestic water piping materials:


Copper piping will last at least half a decade. Copper will generally not interact with the water it carries. It should not be connected to black steel. If this connection is unavoidable, then a properly sized dielectric coupling or fastener must be installed.

It’s available in three types: Type L, Type M, and Type K. Each type has its own different strength:

  • Type L is a thicker-walled pipe and is considered standard piping for water services both inside and out.
  • Type M is a thin-walled pipe, and it’s the most commonly used copper piper inside walls of homes to route water to the water heater.
  • Type K, the thickest-walled pipe, is used mainly between water mains and the meter, for heavy-duty vacuum pump lines, and underground lines.


Because it’s cheaper and lighter than copper, CPVC is a popular choice in domestic water piping uses. It is also easier and quicker to install with solvent cement. CPVC is also immune to corrosion and resistant to scale build-up.


PEX is also less expensive and easier to install than copper, and installation does not require elbows. It is easy to work with and is resistant to corrosion and scaling.

In all cases, whether CPVC, PEX, or copper piping is used, the manufacturer’s recommendations should be followed!