- Copper: Copper is a durable, corrosion-resistant material that is often used for water supply lines. It is also used for drain lines, but it is not as common as PVC or ABS. - Galvanized steel: Galvanized steel is a type of steel that has been coated with zinc to protect it from corrosion. It is often used for drain lines and vents. - PVC (polyvinyl chloride): PVC is a type of plastic that is resistant to corrosion and chemicals. It is often used for drain lines and vents. - ABS (acrylonitrile butadiene styrene): ABS is a type of plastic that is similar to PVC, but it is more flexible. It is often used for drain lines and vents. - PEX (cross-linked polyethylene): PEX is a type of plastic that is flexible and resistant to corrosion. It is often used for water supply lines.