• Iron pipes tend to rust.water pipes image by DSL from Fotolia.com
  
  Water pipes convey treated water to buildings as part of a municipal water system, and also distribute water throughout the building. Water pipes used to be made mainly of iron, but iron rusts, leading to leakages. Rust also tainted the water, making it unsafe for drinking and other uses.
  
  

Polybutylene and Cross-Linked Polyethylene

• Plastic pipes are more durable than iron pipes.water pipes image by Byron Moore from Fotolia.com
  
  Polybutylene (PB) and cross-linked polyethylene (PEX) pipes are two similar flexible plastic water pipes that come in rolls. They require mechanical fittings that are neither cemented nor soldered, and must be approved by local building officials. They're both advantageous due to their flexibility. They can be manipulated during installation and later during use in the home. The main line that supplies water to the house is routed through a manifold that has multiple outputs that connect to an outlet like a bath tub, shower, washing machine, dishwasher or toilet. Polybutylene and cross-linked polyethylene pipes do not require elbows, joints and other couplings, which reduces the cost of labor and materials needed to install them. Another advantage of polybutylene and cross-linked polyethylene pipes is that, because one output connects to an outlet, turning on another faucet does not affect the water flow.
  
  

Copper

• Hard copper is popular in home construction.Perfect Plumbing image by Heydj from Fotolia.com
  
  Copper is favored by plumbing subcontractors. It is expensive and requires more skill to install than plastic pipes. Copper pipes are usually soldered together, but can be fitted together with compression fittings. There are two main types of copper tubes: soft (annealed) and hard (tempered). Hard copper tubes are usually preferred for home work and are sold in coils of 10 to 20 feet. Soft copper tubes are sold in lengths of 60 to 100 feet. Hard copper tubes can be used both inside and outside, and are common in places where the water pipe is exposed. Hard copper tubes do not need much support and are neater in appearance after installation. Soft copper tubes are more flexible and are usually used for repair work because they can be maneuvered around obstacles with minimal cutting and connections.
  
  

Chlorinated Polyvinyl Chloride

• Chlorinated polyvinyl chloride (CPVC) is cheaper than copper.pipework carrying water in a treatment plant image by Heng kong Chen from Fotolia.com
  
  Chlorinated polyvinyl chloride (CPVC) pipes offer a cheaper alternative to copper pipes and can be joined together using crimp ring fittings, PVC cement or compression fittings.