Copper

• Still the most commonly used pipe for plumbing in residences, copper pipe installation is slightly more complicated and is better performed by a professional plumber or subcontractor. Check with your state building codes in regard to approved pipe materials as more states are approving the use of plastics.
  
  

PVC, CPVC and PVC-DWV

• PVC, PVC-DWV (Drain, Waste or Vent) and CPVC pipe are very similar; however, PVC pipe is only approved for cold water lines. CPVC pipe does not soften when exposed to hot water and is approved for both cold and hot water lines. Plastic plumbing pipes are more durable and reliable, and CPVC is less expensive than copper. PVC-DWV are the type of pipes generally used in septic tank drainage systems.
  
  

PB and PEX

• Flexible plastics that are available in rolls are PB and PEX pipes. This type of pipe is not joined by cement or soldering but requires special fittings. Also, due to the flexibility of these pipes, joints, couplings and elbows are not needed when branching out from the main water line. Instead the main water line is connected to a multiple outlet manifold. Each outlet that branches off the main manifold feeds a line to a separate apparatus, such as a faucet, clothes washer or dishwasher, shower or the like. This configuration eliminates temperature changes when showering and flushing the toilet simultaneously. PEX and PB pipe are approved for hot and cold lines.
  
  

Steel

• Steel pipes are another metal material that is commonly used in water lines, generally from the public main line into private residences and commercial buildings. Steel pipes are also more common for use in septic systems, directing sewage drainage out of the house and into the drain field. Steel pipes withstand high water pressure, and larger diameter pipes are more lightweight.