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How to identify polybutylene piping during your walk through

Updated: Jan 19, 2023

What is Polybutylene piping? You may have heard it called PB or PolyB. Some referred to it as the pipe of the future do to this plastic characteristics making it much easier to work with than copper piping. Polybutylene is a form of plastic resin water supply plumbing pipe that was used extensively in homes here on the Outer Banks and in the region built between 1978 and 1995. This pipe was used by builders to save construction costs as it was much cheaper than copper and could be installed much faster.

In the early stages there were many problems with the connections being improperly installed. Plastic connectors came about and that had even higher failure rates. In the early 90's an updated metal band connection proved to be a bit more of a reliable connection if installed correctly, but other problems started to show up. Some believe the oxidants in water have led to failures as well. Some expansion and contraction failures have happened as well as pipe movement and water hammer (when water is turned on and off frequently).

There is an exterior water service piping commonly referred to as big blue (seen below), a bluish color pipe which has a very high failure rate where tree roots are located. There is now a PEX pipe used for the service which at this time is performing well.

How do I know if it is Polybutylene ?

Polybutylene pipe is typically grey, but it can be many other colors as well. Polybutylene pipes are usually marked with the code “PB2110.” The grey piping can usually be seen at or around the water heater, under kitchen and bathroom sinks, and at the wall behind the toilet. Outside, polybutylene is more often blue, and typically is visible at the water meter or entering the home from underneath.

What are the issues with polybutylene?

After 1995 and many reports of the polybutylene pipes bursting and causing massive damage to properties the manfucaturing was halted. Alot of studies showed chemicals in water (especially chlorine) would react with the pipes causing the fittings to be very brittle. Over time these brittle fittings would allow water to to escape without warning. Currently you are not required to replace polybutylene piping with a more reliable pipe, but there are some instances where insurance providers will want all the polybutylene piping replaced. As a home inspector I refer this out to the expert plumbers to better inform you on the piping. Many plumbers I have spoken with recommend going the proactive route and replacing the polybutylene in the entire home to avoid any costly repairs due to failure.


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