Cause · the grey pipe from the suburban years

Poly-B plumbing: how to tell if you have it, why it fails, and what it means for your insurance

Poly-B — polybutylene — is the grey plastic water pipe that went into Canadian houses from the mid-1970s until manufacturers stopped making it in 1998. It is still in a great many of them, and it is the plumbing material an insurer is most likely to ask you about.

Nothing on this page comes from a plumbing company, all of which have a repipe to sell. It comes from the Government of Alberta’s fact sheets on the product, the Insurance Bureau of Canada, and the Canadian class action record — which together answer the questions people actually have: is it in my house, why does it fail, does it have to come out, and what will my insurer do.

Is it in your house? The years, the colour and the fittings

That gives a window of roughly two decades, and it is the first filter. A house built before 1975 with no plumbing renovation since will not have Poly-B, on the Alberta government’s account. A house built or replumbed between the mid-1970s and the late 1990s may.

What it looks like

In practice: look where the water line enters the house, at the pipes above the hot water tank, and in an unfinished basement ceiling. Flexible grey plastic, printed along its length, is the signal. The Canadian settlement notice describes the same thing — usually grey, occasionally black, with acetal plastic insert fittings that are usually grey and occasionally white, held on with a metal crimp ring.

Not the same as Kitec, and not the same as PEX

Poly-B is sometimes confused with Kitec, which was sold over an overlapping period. They are different products: Kitec is typically orange and blue, with brass fittings stamped Kitec or KTC. Modern PEX is a different plastic again, and it is what most Poly-B replacements use.

Why it fails — and why the fitting matters as much as the pipe

IBC names three stresses: chlorine in municipal water, ultraviolet light, and heat. None of them is dramatic on a given day. All of them are cumulative, which is why the question for a Poly-B system is its age and its history rather than whether it leaks today.

That distinction is the most useful thing on this page. The Alberta government separates two kinds of installation: metal insert fittings with copper crimp rings, which it says were the norm in Alberta, and plastic insert fittings with aluminum or copper bands, which it says are reported to be more susceptible to failure. The same pipe, two very different risk profiles — and the fittings are visible, where the pipe inside a wall is not.

What a failure does

A Poly-B failure is a supply-line failure: potable water under mains pressure, running until someone shuts the main. It starts as Category 1, the cleanest tier under ANSI/IICRC S500, but category is a condition rather than a label, and water that sits in building materials degrades. Health Canada puts the start of mould growth at 48 hours in an area with excessive moisture. The burst pipe page covers the first hour of a supply-line failure; it is the same event.

Does it have to come out? What the Code says

This is the sentence to hold on to when someone tells you Poly-B is “illegal”. It is no longer an acceptable material for new work, and it is not a violation to have it. Codes, the Alberta government notes, are not retroactive.

Whether to replace it is therefore not a code question. It is a risk question, and in practice an insurance question — which is the next section.

What insurers say, and what they do not

That is the whole of what the Insurance Bureau of Canada publishes on Poly-B and insurance: some insurers may have exclusions, and you should ask. It is more than IBC says about Kitec, where it says nothing. This site does not name insurers that decline, surcharge or require replacement, because no neutral source does.

If a Poly-B fitting lets go

The event is a sudden and accidental escape of water, which is what standard Canadian cover is written around: IBC states that “sudden or accidental water damage caused by indoor plumbing, heating or air conditioning” is normally covered. Where a Poly-B exclusion applies, the question becomes what that wording excludes — the pipe, the damage, or both — and only the wording answers it. Ask before a failure, not after.

Selling a house with it

No regulator this site could find publishes a Poly-B-specific disclosure rule. BCFSA’s general definition of a material latent defect is the relevant starting point in British Columbia; whether a particular Poly-B system meets it is a question for a lawyer, not for this page.

The class actions, and why they are closed

Canada had its own Poly-B litigation, in three provinces, and a settlement under which the resin supplier would pay a quarter of a replumb and of leak damage without admitting liability. A larger United States settlement, Cox v. Shell Oil, was entered in Tennessee in 1995.

The practical point is the same as for Kitec: anyone finding Poly-B in a house today is outside every claims process that ever existed. The remedy now is a replacement decision and an insurance conversation, not a claim.

Questions people actually ask

Where to read next

• Kitec: the other pipe with a court record
• What replacing it costs
• The first hour of a supply-line failure
• Twelve water situations compared
• Lead and galvanized pipes, and what cities pay
• Every cause, side by side