Whether hiring a plumber or taking on a do-it-yourself plumbing project, the experience can be confusing because of the choice of several types of plumbing pipes. Eventually, pipes' uses tend to blend together. Which type of pipe should be used for water supply, drainage, sewer, and even for the exterior? The answer is not as clear as it may have been in the past when the main pipes of choice were galvanized steel or cast-iron.
PEX, or cross-linked polyethylene, pipe is one of the newest and most popular pipes to hit the plumbing market. PEX is used only to supply water. PEX is a pipe that is rigid enough to withstand the pressures of water supply but flexible enough to weave throughout walls, ceilings, basements, and crawlspaces. PEX has truly delivered water-supply plumbing into the hands of do-it-yourselfers and professional plumbers.
Long-term capabilities untested
May leak with push-fit plumbing fittings
Cannot be recycled
PVC, or polyvinyl chloride, pipe is a drain or vent line type of plumbing pipe. PVC initially gained popularity because it was lighter and easier to work with than traditional galvanized steel pipe. PVC pipe is moderately easy to install and requires little more than a hacksaw and a miter box to cut. PVC glues together with solvents.
Diameters clearly marked on the white surface of the pipe
Inexpensive and can be used for long runs such as for irrigation
The pipe cannot be unjoined and must be cut
Glued pipes can be prone to leaking
Fragile and tends to shatter
Rigid Copper Pipe
Rigid copper is often used for water supply lines within the home. Rigid copper is easily cut with a hacksaw or with a special copper tube cutter. The connection is a different matter, as it requires a practiced hand to solder copper pipe together. Rigid copper pipe is great for water supply because it does not come with any health risks.
Though it is called rigid, this pipe can be slightly bent
Handles heat well
Stands up against intense pressures
Easy to recycle and waste copper pipe even has monetary value
Difficult for do-it-yourselfers to work with due to soldered connections
Develops pinhole leaks
Inside of pipe may eventually corrode and impede water flow
ABS (acrylonitrile butadiene styrene) pipe is mainly used as a vent and drain line. ABS pipe looks very much like PVC pipe, except that it is black and slightly softer.
Stronger than PVC pipes
Good for underground exterior use
Works well in cold temperatures
Often not permitted by building code
Warps and deforms at certain temperatures
Flexible Copper Pipe
Flexible copper pipe or tubing is used for final runs to water heaters, refrigerators, and some sinks. Flexible copper is used only for short runs and can be cut with ease with a hacksaw. It can be bent to fit around corners.
Fits in tight, unusually shaped areas
High heat tolerance
Thin and prone to breaking
Galvanized Steel Pipe and Cast Iron
Two additional types of pipe are sometimes found in older homes and are infrequently installed, especially by do-it-yourselfers: steel and cast iron pipe.
Galvanized steel pipe was used for decades for drainage, water supply, gas supply, and any number of other purposes. While galvanized steel pipe is still around (particularly for gas supply) it is far less used and is never used for water supply in new construction or remodel projects. Each end of the pipe is threaded, and individual pipes are screwed into each other with connecting joints.
Cast iron pipe was often used for sewer and other drainage purposes. Cast iron pipe is still found in many homes. Cast iron pipe is viable until the point that it rusts completely through. Cast iron is very heavy and difficult to cut. Retrofits tend to replace cast iron pipe with rigid plastic pipes such as ABS.
Galvanized steel pipe has the advantage of being extremely strong.
Galvanized steel pipe eventually corrodes and blocks water flow.
Some galvanized steel pipe may pass lead into the water supply.