What it is
Poly-B is polybutylene, a flexible plastic pipe used for hot and cold water supply. It went into houses, townhouses and condos across Canada from about 1978 to 1997, both in new construction and when older homes were replumbed. It hasn’t been installed for many years, but it’s still found in homes today.
Failures come mainly from two things: fittings that crack, sometimes because they were overtightened, and the pipe itself breaking down over time in chlorinated water. A failure usually shows up as a leak at a joint or a split in the pipe, often with little warning.
How to recognise it
- Flexible pipe, usually grey, though other colours exist
- “PB2110” printed along the pipe
- Plastic or brass fittings, often with copper crimp rings
Look where pipes are exposed: at the water heater, at the main shut-off, under sinks and in unfinished basement ceilings. White, red or blue flexible pipe is usually PEX, a different material. Most plumbing is hidden in walls, so the pipe you can see at the tank doesn’t tell you what runs everywhere else.
Why it matters
Insurers in BC often ask whether a home has Poly-B. Some decline coverage, raise the water-damage deductible or require the pipe to be replaced, so the answer can affect whether and how you can insure the home. Replacing it means opening walls and ceilings, so it’s a planned project rather than a quick repair.
In a condo or townhouse, Poly-B may run through common areas as well as the unit, which makes it a strata matter. The minutes and depreciation report should show whether replacement has been discussed, planned or done.
What to do
- Before subject removal: have a licensed plumber confirm how much Poly-B there is and quote replacing it, then call your insurer with what you’ve found.
- In a strata: read the minutes and depreciation report with your realtor or lawyer.
- If it stays for now: learn where the main shut-off is, and check the fittings at the water heater and under sinks for drips.
What our inspection covers
We identify the supply piping wherever it’s visible: at the water heater, the main shut-off, under sinks, and in open ceilings and crawlspaces. We note leaks, staining and the type of fittings, and the report says where we saw Poly-B and where piping was hidden. We don’t open walls, so we can’t confirm the material in concealed runs or say how much of the house it serves. That’s a job for a licensed plumber.
Buying a home built or replumbed between the late 1970s and the late 1990s? Book an inspection and tell us your subject-removal date.
Reviewed October 26, 2026 by Nick Hawley, Watch House Inspections. General information, not advice about a particular home.