OK, you've just finished your MA home inspection and your inspector has noted the presence of water supply lines in the home made of Polybutylene Plastic, also known as "PB pipe". So, what's the scoop?
PB pipe was manufactured between 1978 and 1994 for use as piping in home plumbing systems. It offered plenty of advantages over other materials such as flexibility, ease of installation, resistance to freezing, and most importantly - it was inexpensive. PB pipe was installed in roughly 6 to 10 million homes in the Unites States during that period. Despite its strengths, production was ceased in 1994.
PB pipe has experienced a higher than normal rate of leaks or plumbing line failures in comparison to more common supply piping materials such as copper, CPVC, or PEX. Bear in mind that NO supply piping materials have a failure rate of zero. There were several Class Action Lawsuits involving PB pipe.
The very first installations of PB pipe had Acetal fittings, made of a hard gray (or sometimes white) plastic, which were inserted into the pipe material and then secured in place with an aluminum metal band (or "crimp ring"). The Acetal fittings were problematic and prone to cracking and leakage due to over-crimping and/or the different expansion characteristics of plastics. As a result, fittings made of copper or brass were introduced, as well as more durable copper crimp rings. Although the metal fittings are more reliable, they too may suffer failures. Additionally, there were a number of other factors that contributed to the leaks associated with PB plumbing systems. Overall, approximately 90% of leaks occur at the joints in the piping due to poor connections using plastic insert fittings.
A typical home inspection cannot and will not determine if PB pipe is about to leak simply by looking at the outside of the pipe or operating the water fixtures.
Here's my first consideration: There are NO current requirements that existing PB pipe be removed from a house - however some prefer to remove it and update to more modern piping materials such as copper or PEX. PB pipe is no longer an acceptable plumbing supply line material for NEW houses. Keep in mind that your seller(s) have probably been aware of it and lived with it since it's installation.
Here's the reality: There is no single course of action that is recommended for consumers with homes containing PB pipe. For the majority of consumers I have worked with, they simply do nothing and continue to live with the piping. In my area there are several housing developments that were plumbed entirely with PB pipe starting in the mid-80's, I continue to see many, many of these homes on a regular basis. Some plumbers or websites may recommend (or insist) replacing the entire system even if there have not been any problems.
The bottom line is: The course of action you wish to undertake should take into account your personal level of risk aversion, the types of materials used, the age of the system, as well as past performance. Do your homework on line. Talk to other homeowners in the area. Understand the material and its risks. Consult a licensed plumber or plumbers for their opinion, without inferring that there is money to be made, if you have any additional questions or concerns. Feel free to email me as well.