Plastic water pipes are gaining popularity in many communities. They are strong, cheap, and easier to install than traditional copper piping. In addition, plastic piping doesn't suffer from the same corrosion that can degrade copper pipe over time in areas with acidic water. In spite of its advantages, however, plastic water pipe does have some serious risks and drawbacks that home builders should be aware of before they install plastic pipping.
Plastics, such as those used in water pipes, can leach out of the pipe into water. This contamination can increase the risk of a number of serious diseases. Polyvinyl chloride (PVC), a plastic used to make many water pipes, can cause birth defects and genetic changes; sensory problems, such as deafness and vision failure; organ problems, such as indigestion, ulcers and liver dysfunction; skin diseases and even cancer. Other common plastic ingredients used in pipes, such as polyethelyne, are also linked to cancer. The degree of health risk from using plastic pipes is still under study.
Consumers generally want their water not to have any strong flavour or smell. Unfortunately, plastic water pipes can give water a bad taste or aroma, particularly when the pipes are new. According to Science Daily, a panel of taste experts assembled by the American Chemical Society studied the taste and aroma of water after it had been left sitting in water pipes. The panellists described the water as having flavours and aromas like "waxy plastic citrus" and "burning plastic." Fortunately, the tastes go away after the plumbing has been in use for a few months.
Some pipes built between 1978 and 1995 used pipes made from a type of plastic called polybutylene, which was cheap and easy to install, making it seem like a good alternative to traditional copper piping. Unfortunately, poly pipes do not hold up over time. They react with certain additives in the water supply, such as chlorine, which causes the pipe to flake and fracture, leak or completely fail. A poly pipe failing can flood your basement or wall cavity, causing extensive damage to your house. Note that this problem doesn't apply to PVC, CVPC and other modern pipes, which hold up well over time.