A system of pipes used for water supply and drainage in a building. Plumbing can also sometimes be used to describe HVAC ducts, but is not commonly used this way.
There are many types of water plumbing pipes. The main ones that you will come across in Oregon homes are ABS, PVC, cast iron, galvanized, copper, CPVC and PEX.
ABS and PVC are commonly confused with each other. ABS pipes will normally be found in black and PVC are white. Otherwise, they will look about the same. Both can be found in walls and in crawlspaces, however, ABS is more common in the crawlspace than PVC.
ABS pipes are used for drain lines and are more commonly found as 2”, 3” and 4” drains in crawlspaces. ABS is used mainly under homes because it is strong and shock resistant, so it is less of a risk of breaking them when crawling around, over or under them. It is also better at handling extremely cold temperatures.
PVC pipes are also used for drain lines but are more commonly found in walls because it is better at muffling the sound of running water. PVC is more flexible than ABS but is less durable.
ABS plumbing:
PVC plumbing in crawlspace:
PVC plumbing being installed in a wall:
Cast iron plumbing is a hard, brittle mixture of iron and carbon that can be cast into a mold. It is a heavy, black material and is used in many ways, from cooking pans to drain line plumbing. When used for plumbing it is found being used for drain lines, especially as elbows and as large, 4” drain pipes that go into the ground to exit the house. Cast iron pipes are not often used in residential plumbing today because of its weight which can lead to sagging, sinking or cracking and can also corrode and clog due to the buildup.
Galvanized pipes are steel pipes that have been dipped in a protective zinc coating to prevent corrosion and rust. It was commonly installed in homes built before 1960. Unfortunately, the dream of galvanized plumbing solving rust issues was not lived up to and was replaced with ABS and PVC piping because it often rusts out, clogs and creates sewage leak issues.
Cast iron and galvanized plumbing are often seen being used together. Galvanized pipes will be seen as freshwater lines (normally ¾” - 1” in size) or sink, shower and small appliance drains (normally 1 ½” - 2” in size). Cast iron pipes are normally used for the elbows and curves in the pipes and are used for toilet drains and main drains, which are the ones that all of the other pipes drain to before exiting the house.
Copper is a type of metal that is brownish-orange in color. It is used in plumbing to deliver or carry safe drinking water for thousands of years because of its corrosion resistance and dependability. It is easy to recycle, bend, join to other materials and is safe for water use. It is still used today and is one of the best plumbing supply materials. The only major drawback to copper is cost. It is most commonly found as ½” or ¾” piping.
CPVC is a type of plastic piping that was introduced in 1959 for water supply lines. It is similar to PVC but is more yellow-ish in color. It is more rigid and tolerant of higher temperatures than PVC but is more brittle and breaks quite easily. It is mostly found as ½” - 1” piping.
PEX is a type of flexible plastic. It is a newer type of plumbing that is replacing copper and galvanized water supply lines in construction and remodeling. It will normally be found in blue (for cold water) and red (for hot water). It can also come in white or gray which are both used for either hot or cold water. It is found as a ½” - 1” pipe, used primarily for supply lines. It is prone to being chewed through by rodents because it is soft.
