Pipes supply water, and sometimes natural gas, to your house and drain used water and waste back out. They are also used outside your home to supply water to irrigation systems and for drainage. With so many piping materials available in such a wide variety of sizes, it's easy to feel confused or overwhelmed.  This guide will help you get a basic understanding of installed pipe systems in your home and help you choose the right piping material for your next plumbing project.

Preparation
Before replacing old pipe, be sure to consult local building codes and regulations. Some areas of the country require installation by a professional, while others dictate the types of materials required for certain installations. Most of the time permits are not required for repair or replacement work, but they are required if you're running pipe in a new location. Always check with your local government's building inspection department to be sure of code and permitting requirements.

Types of Lines
The first step in working with pipe is to identify whether the pipe will function as a supply line, drain line or gas line.

• Water supply lines carry water from a main or well to faucets and fixtures in your home

• Drain-Waste-Vent, or DWV, lines remove waste and gases from your home.

• Gas supply lines carry gas to your appliances.

Materials
The next step is to choose the right material, based on the function it will serve. All pipes are made of plastic or metal, and each type is used for specific applications. Refer to the tables below to learn more about some common types of pipes for water supply, drainage and gas applications and how they are used.

Water Supply:

Drain-Waste-Vent (DWV):

Gas:

Pipe Sizes
There are several plumbing piping dimensional standards. The most common examples include schedule 40, schedule 80, copper tube size (CTS), Standard Dimensional Ratio (SDR), cast iron soil pipe and sewer main/sewer and drain. It is imperative that you know the sizing standard of the pipe you need.

Always check local code requirements to confirm the materials you select meet required standards. If you're not sure of the correct size or grade when replacing pipe, bring it the store so it can be matched.

Tools to make your job easier
Cutting Tools: Tubing cutters will help you slice through plastic with ease while cast-iron snap cutters will make short work of cast-iron pipes.

Hangers: Horizontal pipes need support every 4' to 6', so you'll need to install hangers. Types of hangers include wire hooks, copper two-hole straps, plastic hangers and plumber's straps. Always follow local code requirements.

Water Hammer Arresters: Also called mufflers, these devices stop the banging sound you hear when valves on washing machines, dishwashers and faucets slam shut. They also help prevent damage to both pipes and faucets.

Vents and Traps: Vents filter air and gas out of pipes as well as provide air to help water flow. Traps are installed below sinks and keep sewer gases and other noxious vapors out of your house.

Caps: Caps allow you to temporarily seal off the end of a pipe so you can turn the water back on.