Polybutylene pipes have been proven as ineffective and can fail without warning. They are no longer in use, (Class Action lawsuit) but many homes and buildings still have them. Expert question the safety of PVC pipes as well. Some brass fittings fail when they are dezincified.
Polybutylene pipes are known to pose a danger to water supplies and property. Re-piping can prevent these problems from occurring. If your home or building has galvanized piping and is over 30 years old, or if you notice when you flush a toilet or turn the water on, that the water pressure drops in another part of the house or water temperature fluctuates (i.e. sudden bursts of hot or cold water in the shower), you may need to do re-piping to your home or building.