Polybutylene plastic plumbing supply lines (PB2110) were installed in a house at a recent home inspection in Oak Harbor on Whidbey Island.  Polybutylene has been used in this area for many years, but has had a higher than normal failure rate, is no longer being widely used, and has been the subject of class-action lawsuits. Copper and Brass fittings used in later years have apparently reduced the failure rate. This particular house has copper fittings and PB2110 supply piping.  More information about PB water supply piping can be round at http://www.pbpipe.com.