Plumbing pipe has two major categories, which are plastic and metal. In the plastic category you have polyvinyl chloride (PVC), Chlorinated polyvinyl chlorined (CPVC), PEX Pipe and Poly Pipe. The metal category  has Copper, stainless steel, and galvanized steel.

Listed are the descriptions for each type of pipe,

PVC Pipe - is usually white in color but sometimes can be grey, PVC is used to transport high pressured cold water as hot water will cause the pipe to warp. It comes in sizes ranging from 1/2 inch to 4 inches in diameter.

CPVC Pipe - is also PVC pipe but it has received extra chlorination and comes in a yellow color. CPVC can handle both hot and cold water and is more flexible and thinner than PVC pipe and has the same diameter as copper.

PEX Pipe - or polyethylene pipe has the same diameter as copper also and can be used for both hot and cold water. PEX has a higher heat resistance than other plumbing pipe so it is often used in water based heating systems. PEX comes in a creamy white color, also in red and blue colors.

Poly Pipe - is used to transport high pressurized water to and from the home outside and is usually buried underground, poly pipe is black in color and is extremely ridigid.

Copper - is the most common used in the home but it is quite expensive, it is resistant to corrosion and can stand up to higher temperatures.

Stainless Steel - is not commonly used since it is expensive and harder to find. Stainless steel is mostly used in marine environments since it can stand up to salt water.

Galvanized Pipe - carries water out of the home and has a dull grey color and does not rust. This type of pipe is not being used as much due to expense.

Hopefully this article gives you a little better understanding of the different types of pipe and will help you in the best decision for your home or business.