A Primer on Polybutylene
In the very late 1970s, they introduced a new type of pipe for potable water plumbing in homes. Polybutylene was touted as the next great thing and to the early 80s to the mid-90s was installed in literally millions of homes throughout the nation.
Polybutylene was most typically supplied in a bluish gray color and was stamped along its length with some identifying nomenclature including "PB 2110." In addition to being utilized for potable water supplies within the home in some cases the main supply line to the water source, either a well or utility company provided water source, was Polybutylene.
Polybutylene rapidly became very popular with builders because it was considerably cheaper than copper and required no soldering and was much easier to install because of its flexibility. The only tool required was a crimping tool for securing junctions and since soldering or even gluing was no longer required workers no longer needed to be as skilled as previously required.
With lower material costs, lower installation costs, and the predicted 50 year lifespan Polybutylene rapidly became popular. Unfortunately, the predicted 50 year lifespan turned out to be wishful thinking.
Within 10 to 12 years, Polybutylene started to show leakage problems. Initially, these were at the connectors where plastic fittings were compression type or secured by metal, aluminum, and then later copper or brass, crimp rings. In some cases improperly installed crimp rings could bite into the plastic causing earlier failure. In other cases the fitting itself cracked under the stress of the crimp ring and water pressure.
The fittings were improved by replacing the plastic with copper fittings coupled with metallic crimp rings. These proved to be more reliable but not a perfect fix.
Even though the fittings improve the situation, the pipe itself began to fail away from the fittings. When Polybutylene was first introduced, there was no history of its compatibility with water purification products such as chlorine and other disinfectants. The pipe started to deteriorate on the inside, so there were no visible signs of imminent failure. Sometimes the failure took the form of a slow leak and other times pipe simply burst. Well water, being untreated with chemical disinfectants, may reduce the frequency of leaks, but unfortunately does not eliminate them.
In an effort to reduce the number of fittings required in new construction manifold for introduced which would allow home runs from the supply to the actual water fixtures throughout the house. This reduced leakage problems, but of course did not eliminate them. The manifold system, however, is still retained in new construction utilizing PEX supply lines and for the same reason, allowing home runs and a reduced number of required fittings.
From a home inspection standpoint, there is little indication on the pipe itself of imminent failure. What can be observed are otherwise unexplained moisture or staining on the structure of the house. Confirmation of leakage in concealed areas obviously requires invasive techniques that lie outside of the typical scope of a home inspection. Once in a great while failure may be indicated by an actual leak, but since these are typically a result of the pipe actually bursting corrective measures have generally been taken prior to the home inspection.
Any water supply pipe leaks can cause a great deal of damage structurally and also support mold growth in concealed areas of the home. The history of Polybutylene supply lines indicates a much higher likelihood of failure and subsequent damage.
During a home inspection, your home inspector may recommend further evaluation by a plumbing professional if he encounters Polybutylene supply lines. This recommendation is to provide professional guidance in considering a course of action and to assess whether there may be any concealed leaking undetectable during a visual inspection.
Polybutylene was involved in several class action lawsuits and the manufacturers, DuPont and Shell Oil, provided settlement funds in the amount of nearly $1 billion. These funds have been depleted and is no longer available to homeowners.