Which pipe for which job

Entry in Choosing pipe and trouble · Updated October 29, 2026 · Written by the Know Your Pipes editors from the sources listed under References

There is no single best pipe for plumbing: the right material depends on the job, such as hot and cold supply, the buried service line, drains and vents, or gas, and on what the local plumbing code allows. Each material has temperature, pressure, sunlight and water-chemistry limits that rule it in or out.

1 Matching material to job

2 Hot and cold supply

Three materials carry most hot and cold water inside US houses. PEX tubing is rated for no less than 100 psi at 180°F and 160 psi at 73°F under industry standards, and some tubing also carries an 80 psi rating at 200°F.^[1] It bends around obstacles, which reduces the number of fittings. CPVC made to ASTM D2846 is rated for continuous service at 180°F and 100 psi and is joined with solvent cement.^[2] Copper tube has the longest track record; the Copper Development Association suggests Type M as a minimum for water distribution above and below ground, where codes allow it.^[3]

PVC does not belong on hot water. One maker lists a 140°F maximum operating temperature for PVC and names CPVC as the material for distributing drinking water inside a building, with PVC limited to carrying it up to the building.^[2] Model codes and their local amendments set the exact list of approved materials; see plumbing codes.

3 Water service lines

The buried line from the street or well needs a material approved for burial and for the pressure it will see. For copper, the Copper Development Association suggests hard Type M in straight lengths joined with fittings, or soft Type L where coils are more convenient.^[3] One PEX maker states its pipe is approved for direct burial in soil or concrete.^[4] Polyethylene and PVC are also used for cold-water service; see polyethylene water service pipe. Burial depth below the local frost line and the meeting point with the utility's line are set locally.

4 Drains, waste and vents

Drain, waste and vent (DWV) pipe carries water by gravity and air for venting, not pressure. One maker's catalog lists white PVC and black ABS for DWV, adding that ABS sees more use in western states and that each takes its own cement.^[2] Black ABS holds up well outdoors because carbon black in the compound screens sunlight, which is why it is used for exposed vent pipes; non-black ABS is not recommended outdoors.^[5] Cast iron is quieter and common in older houses, and copper DWV tube is made for the same service.^[3] Joining ABS to PVC needs a listed transition fitting, and codes vary.

5 Gas, outdoors and special cases

Gas piping, whether black steel or CSST, is a separate system governed by the fuel gas code and installed or altered by qualified, licensed people, never as a do-it-yourself job.

Outdoors and in sunlit spaces, PEX should not be installed unless it is buried or protected from direct and reflected sunlight.^[6] Painted or buried plastic fares better; see sunlight and UV limits.

Water chemistry can also steer the choice. The Copper Development Association lists aggressive hard well water, soft acidic water and high flow velocity among the causes of copper corrosion problems.^[3] Where pinhole leaks recur, a water analysis usually comes before a repipe decision. Sizing is a separate question covered in pipe sizing basics.