Polybutylene, usually called Poly-B, was widely used for residential water supply lines in British Columbia from roughly the late 1970s into the mid 1990s. It was inexpensive, flexible and quick to install. It was also prone to failing from the inside out, which is why it is now one of the most common reasons a Lower Mainland homeowner ends up replacing supply piping that looks perfectly sound from the outside.
If your home was built or repiped in that window, it is worth knowing what you have.
How to identify Poly-B
- Flexible grey plastic pipe, roughly the diameter of copper, though blue and black were also used
- Often stamped with the marking PB2110 along the pipe
- Joined with crimped metal or plastic bands rather than soldered fittings
- Most visible at the hot water tank, under sinks, and where pipe enters the ceiling in an unfinished basement
Check the water heater connections first - that is usually the easiest place to see supply pipe in an otherwise finished home. Note that Poly-B is a supply material; it is not the same thing as the ABS drain piping in the same house.
Why it fails
The failure mode is what makes Poly-B awkward. Chlorine and other oxidants in treated municipal water degrade the pipe wall gradually from the inside. Micro-fractures form and propagate outward, so the pipe can look fine right up until it does not. Failures also concentrate at the crimped fittings, where original installation quality varies enormously.
- Deterioration is internal, so visual inspection is not a reliable indicator of remaining life
- Failures often present as a pinhole leak rather than a dramatic burst, so water can run behind a wall for a long time before anyone notices
- Hot water lines generally degrade faster than cold
- Fittings are a frequent failure point independent of the pipe itself
Signs it may be reaching the end
- Small unexplained leaks at fittings, particularly near the hot water tank
- Staining, bubbling paint or soft drywall on a wall that carries supply pipe
- A drop in water pressure that cannot be traced to a fixture or the municipal supply
- Flaking or discoloured material visible where pipe is exposed
- A water bill that has crept up with no change in household use
What drives the cost of replacing it
We do not publish a flat figure for repiping, because the honest answer is that it varies more than almost any other job we do. What we can do is set out what moves the number, so you can judge a quote sensibly.
- The size of the home and the number of bathrooms and fixtures the new lines have to serve
- How accessible the existing runs are - an unfinished basement is a very different job from a finished three-storey with no crawlspace
- Whether the work can be staged around the existing system or the house needs to be off water
- How much drywall has to be opened, and who is restoring it afterwards
- The replacement material chosen and the fixture connections involved
Repiping is quoted on site after we have seen the actual runs. Any firm number offered before someone has looked at your specific home is a guess, and it will change.
The insurance question
This comes up in almost every Poly-B conversation and it deserves a straight answer: it depends entirely on your insurer and your policy, and it changes over time. Some carriers in BC ask about Poly-B at renewal. Some price it differently. Some treat resulting water damage differently from the cost of the pipe itself.
We are plumbers, not insurance advisers, and we will not tell you what your policy covers. What we can do is document what is in your home and what was replaced, which is the information your broker will ask for. Speak to your own insurer or broker directly before making assumptions in either direction.
Replace now, or monitor?
There is no single right answer. A home with Poly-B that has never leaked is not an emergency. But the material does not improve with age, the failures are internal and hard to predict, and the cost of a planned repipe is generally far more controllable than the cost of water damage plus a repipe. If you are already renovating, opening walls, or planning to hold the property long term, doing it deliberately is usually easier than doing it urgently.
Got the problem we just described? We answer 24/7 across Surrey, Langley, Vancouver, Burnaby, Coquitlam, Delta, White Rock, and Richmond. Call Mr. Plunger Plumbing & Drainage at (604) 870-1442 — real plumber on the line, exact ETA before dispatch, up-front quote before any work starts.