Doing your own plumbing can be a confusing experience because you have a choice of several kinds of pipe. They can blend together: which to choose?
The answer isn't as clear as it may have been in the past--when the choice was limited to galvanized pipe or galvanized pipe. Here are the main types of plumbing pipes you may find in your home remodel:
For: Water supply lines only and for do it yourselfers.
Flexible, color-coded plastic piping, PEX has truly delivered water-supply plumbing into the hands of DIYers.
PEX is easy to cut, simple to join. PEX yields to logic, and it makes 90 degree curves with ease. For most homeowners, plumbing supply lines with PEX is a no-brainer.
2. PVC - Polyvinyl Chloride
For: Drain and vent lines.
PVC pipe has been a very big deal in the plumbing industry in the last few decades, because it is lighter and easier to work with than traditional galvanized steel pipe.
You will mainly be using PVC pipe for drain or waste pipes, or stacks (those pipes you often see sticking up out of the roofline), and not as supply pipes. PVC pipe is easy to install, and requires little more than a hacksaw, miter box, and solvents which essentially "glue" the pipe together.
Diameters are clearly marked on the white surface of the pipe. If not easy to read, diameters can be determined with a sizing tool such as Pi-Piper.
3. Rigid Copper
For: Water supply lines and for either professional plumbers or motivated DIYers.
This is your water supply pipe. Rigid copper is easily cut with a hacksaw or Skilsaw, or with a special copper tube cutter. Connection is a different matter, as it requires a practiced hand to solder copper pipe together (advice: buy extra copper pipe to practice on).
Rigid copper pipe is great for water supply because it does not carry the health risks that PVC has.
For: Drain and vent lines.
ABS pipe looks very much like PVC pipe, except it is black. ABS is basically the "older version" of PVC, and is often not allowed anymore by plumbing codes. Like PVC, ABS pipe is used for drain and vent pipes. If working with ABS, the best advice is to replace with PVC.
5. Flexible Copper Tubing
For: Final runs to water heaters, refrigerators, etc.
Flexible copper is used for short runs. You have probably seen it leading up to your water heater, or for cold water supply in tight spots.
Flexible copper tubes can be cut with ease with a hacksaw, and bent to fit around corners. Because it does not stand up well against extreme temperatures, flexible copper is not recommended for exterior use.
6. Galvanized Steel
For: Continuing previously-installed galvanized steel pipe.
Galvanized iron pipe is the pipe of popular imagination: it is what we think of when we think about plumbing pipe. It is made of galvanized steel, with each end of the pipe threaded. Individual pipes are screwed into each other with connecting joints.
While extremely strong, galvanized pipe is rarely used for new home construction, and is not recommended that the do it yourselfer run new lines with it.
7. Cast Iron
For: Sewer lines.
Older cast iron pipe is still found in many homes. Despite its outside aged appearances, cast iron is still viable for use until the point that it rusts completely through.