Gas and Water Pipes Buying Guide

Replace a cracked pipe quickly and prepare for your plumbing project using PVC and copper pipes

Pipes carry water, waste, and occasionally natural gas in and out of your home, so when they crack, they need to be replaced as fast as possible. This guide will teach you which pipes to choose for your next plumbing project, and how to measure pipes properly.

Tip: Before replacing or installing new pipes, always 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. Permits are not usually required for repair or replacement work, but they are required if you are running pipe in a new location.

Copper vs. Plastic Pipes

The type of pipe you choose for your project depends on its purpose. Will it be a supply, drain, or gas line?

Refer to the tables to learn more about some common types of pipes for water supply, drainage and gas use.

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

Materials Points to Consider


  • Primarily used for hot and cold water applications in residences
  • Often replaces copper pipe in interior applications
  • Available in 10-foot and 20-foot lengths and diameters of ½-inch to 2-inches
  • Pipe and fittings join with primer and solvent cement or SharkBite® fittings
  • SharkBite® fittings can be used as an efficient alternative to solvent cements or


  • Used for hot and cold water interior pipes in residences
  • Easy to maneuver around obstructions without using elbows
  • Available in 100-foot rolls with diameters of ¼ to¾-inch
  • Joins with plastic grip or metal crimp fittings or SharkBite® fittings
  • SharkBite® fittings can be used as an efficient alternative to solvent cements or

PVC(polyvinyl chloride)

  • Used for cold water applications only
  • Commonly used for irrigation systems
  • Available in 10 and 20-foot lengths
  • Pipes used for pressure applications range from ½-inch to 2-inches in diameter
  • Join with primer and solvent cement or mechanical couplings


  • May be used with hot or cold water
  • Lightweight and durable
  • Fits easily in tight places
  • Available in 10 or 20-foot lengths in diameters of ½-inch to 2-inches
  • Use M (red) and L (blue) rated copper pipe for water service and distribution
  • Use M (red)-rated copper for indoor water distribution
  • Hard copper is used for water applications and is joined by soldering, brazing,
    a compression coupler or SharkBite® fittings
  • SharkBite® fittings can be used as an efficient alternative to soldering

Drain-waste-vent (DWV) lines remove waste and gases from your home.

Materials Points to Consider

PVC(polyvinyl chloride)

  • Available in 10-foot and 20-foot lengths
  • Pipes used for Drain-Waste-Vent are 1½-inches or larger
  • Join with primer and solvent cement or mechanical couplings


  • Used in mobile homes, residential and commercial sanitary systems
  • Strong, light and easy to cut
  • Joins with solvent cement
  • Transition fittings allow for connections to steel, copper or cast iron
  • Joins with plastic grip or metal crimp fittings

Cast Iron

  • Strong and durable
  • Easily joins to plastic pipe with transition fittings
  • Hubless pipe is joined with a shielded no hub coupling
  • Hub-and-spigot cast iron pipes should be installed by professionals

Gas supply lines carry gas to your appliances.

Materials Points to Consider

Black Malleable, (aka Black Malleable Iron, Galvanized Malleable Iron, Cast Iron)

  • Used to transport natural and propane gas from the street or a tank to the
  • Usually comes in lengths of 10 or 20-feet in diameters of ½ to 1-inch


  • Should be type L (green) or K (blue) when used to transport gas
  • Use M (red)-rated copper for indoor gas distribution
  • Not recommended for use with natural gas in some areas as sulfur content can
    cause interior flaking
  • Soft copper is used for gas applications and is joined using compression
    couplers or a flare joint


  • May be used as main gas supply to the home
  • For underground use only
  • Wire run beside pipe allows detection by metal detectors for repairs


  • Available in coils, for easy installation with minimal joints
  • Connected by heat fusion or mechanical fittings
  • Durable and provides long-term resistance to environmental conditions

Measuring Pipe Sizes

There are several plumbing piping dimensional standards, and it is crucial that you know the exact size pipe you need before installation.

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

Measuring Pipes - Gas and Water Pipes

For replacement jobs -- you need a new pipe to exactly match the damaged one -- grab a ruler. Place the ruler over the opening at the end of the pipe, straight across the middle of the hole where it’s the widest. Measure from outside edge to outside edge to give you the width of the pipe, including the pipe material itself. That is your outside diameter (OD).

Now, measure along the center of the pipe again, but this time from inner edge of the material to inner edge -- measuring the actual opening of the pipe. That is your inside diameter (ID).

Armed with these two measurements and the pipe material, you can accurately select an identical replacement pipe.

Tools Needed

Make your job easier with some basic cutting tools, hangers and caps.

  • 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 feet, 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.