What Is Poly-B?
Polybutylene, commonly known as Poly-B, is a flexible grey (sometimes off-white or black) plastic pipe that was used extensively in residential plumbing in Canada from the late 1970s through the mid-1990s, prized at the time for being inexpensive and easy to install.
Why It's a Concern
Poly-B itself is generally considered to degrade slowly when exposed to chlorine in municipal water over long periods, becoming brittle over time. In practice, the more common failure point is at the fittings and connections rather than the pipe itself — particularly where improper installation techniques were used.
How to Identify It
Poly-B pipe is typically grey and flexible, often connected with copper or plastic fittings secured with a metal crimp ring. It's commonly visible at the water heater, under sinks, or in a mechanical room. Homes built or plumbed between roughly 1978 and 1995 are the most likely candidates.
What this means for you
Poly-B was the subject of a class-action settlement in the late 1990s, though that claims period is long closed. Many insurance providers in BC now ask specifically about Poly-B plumbing, and some require it be replaced or may adjust coverage terms accordingly.
What to Do If You Find It
Full repiping is the most common long-term solution, though it's a significant cost many buyers factor into their offer or plan for down the road. In the meantime, monitoring connections for signs of wear and addressing any visible issues promptly can help manage risk.