Learn The Basics of PEX Pipe For Do It Yourself Plumbing

Crimping PEX Pipe onto Copper Pipe
Crimping PEX Pipe onto Copper Pipe. Getty / Banks Photos

Basic household plumbing is now accessible to even the most plumbing-averse homeowner.  This revolution is due to many factors, but chief among them:  the introduction of PEX pipe for water supply lines.

PEX Has Replaced Galvanized and Copper Pipe For Most DIYers

Traditional galvanized pipe and copper pipe have learning curves that few homeowners want to tackle, especially if the plumbing project is minor.  Professional plumbers still use both types of pipe, as well as PEX.  Many plumbers prefer copper.

But for do it yourself homeowners, PEX offers so many advantages that it can tip the balance from calling a plumber to doing the project or remodel yourself.

5 Reasons You Want To Work With PEX

  1. Inexpensive:  PEX pipe is about 66% cheaper than copper pipe.
  2. Color-Coded:  While not required, you can use red pipe for hot, blue for cold.
  3. Simple Fittings:  PEX can be joined with stab fittings (Sharkbites) or by crimping.
  4. Easy To Cut:  PEX can be cut with a scissors type cutter, no saws involved.
  5. Flexible:  PEX can make 90 degree turns.  For straight runs, PEX has some wiggle room.

1.  Inexpensive:  PEX vs. Copper

PEX is far cheaper than copper pipe, typically 1/3 the cost of copper.  Copper pipe prices fluctuate wildly, since this is a commodity dependent on market forces.  Currently,

  • PEX Price:  100 feet of PEX is about $0.28 per linear foot (total:  $28).
  • Copper Price:  100 feet of straight copper pipe is $0.90 per linear foot (total:  $90).

2.  Color-Coded:   Colors Designate Hot, Cold, or Other

  • Red:  For hot water supply
  • Blue:  For cold water supply.
  • White:  Can be used for either hot or cold.  Also, it can be used for branch lines that are visible,  such as for a toilet supply.  White is a less obtrusive color than red or blue.

These colors are just for your convenience.  Plumbing code does not require that pipe color match the type of water supply.  

3.  Simple Fittings:  Crimp, Stab (Sharkbites), or Clamp

There are three ways to join PEX

  1. Crimp (Copper Rings):  Shown in this picture is the basic way of joining PEX tubing, using brass fittings, copper rings, and a crimping tool.
  2. Stab (Sharkbites):  Stab-in fittings, often known by the Sharkbites brand name, require no tools.  PEX pushes into the fitting and remains firmly in place, due to small teeth on the inside of the fitting.
  3. Clamp (Steel Rings):  Similar to copper rings, clamp rings encircle the pipe and are forced tightly shut by a special tool.

4.  Easy To Cut:  Rotational or Scissors-Type Cutter

Because PEX is soft, it is easier to cut than copper or galvanized pipe:

  • Rotational Tool:  This cheap, razor blade-equipped tool rotates around the pipe to cut it.  Usually 5 or 6 turns are enough to make the cut.
  • Scissors-Type:  Sharp tube cutters allow you to cut PEX by hand in one snap.

5.  Flexible:  Bend Radius For PEX

PEX can be bent 90 degrees (right-angle) to a radius that correlates with pipe diameter:

  • 1/2" PEX:  Radius of 5".
  • 3/4" PEX:  Radius of 7".

More Information

PEX Has Material "Memory"

PEX can be bent, twisted, or crushed, and it will return to its original shape.  Application of low heat to the pipe will help it return to the original state.

You Will Mainly Use 2 Sizes

  • 3/4" PEX:  Used for the main water line that comes out of the water heater or from the cold water pipe that enters the house.  Note, though, that the first 18" of pipe that extend from the water heater cannot be PEX.
  • 1/2" PEX:  For branch lines that extend off of the main line.  To use a metaphor, if 3/4" PEX is a tree trunk, then 1/2" PEX are the branches.  These branches service individual areas, such as a shower, bathroom sink, kitchen sink, bathtub, etc.