The Plumbing Rough-In

Plumbers work with three basic categories of supplies. There are the supply pipes, that deliver the clean water into the house and to the plumbing fixtures, such as the sinks, toilets, and washing machine.  There are the waste pipes that drain the water and  waste from the fixtures.  Lastly, there are the fixtures you see and use.

The Supply Pipes

Starting with the service line from the source – perhaps you have a municipal water supply, maybe a well on your property – the supply pipes extend into the home. The main cold-water pipe, called the trunk line, then divides, sending water both to the water heater and to the many branches that supply the fixtures in the house. The cold water supply is paralleled by a hot-water trunk line and a second set of branches that provide the supply of hot water to the fixtures that require both. As with the blood vessels in the body or the branches of a tree, the pipes step down in size as the extremities of the system are reached.

Supply pipes can be iron, copper, or one of numerous varieties of plastic. Copper and plastic pipes are the rule today, but your plumber will look to the specifications to indicate what your job requires. In general, copper is more durable and expensive, plastic cheaper and easier to install. Whatever the material used, the pressure in the system is maintained at all times, so the pipes must be tightly joined. With copper, the joints are soldered; with plastic they're fastened with a solvent cement.