Poly-B Pipe Guide for Homeowners

Identifying it

Poly-B is a flexible plastic pipe, usually grey but sometimes white or black. It is often stamped with "PB2110" or similar markings along its length. Check the places where supply pipe is visible:

• At the water heater connections.
• Where the main water line enters the basement.
• Under sinks and behind toilets, at the stub-outs.
• In an unfinished basement ceiling.

Do not confuse Poly-B with PEX, a newer flexible pipe that is also common. PEX is often red, blue or white and carries "PEX" markings. If you are unsure, take a clear photo of the pipe and its printing, and ask.

Fittings and failure

Poly-B does not always fail, and many installations have lasted a long time. Concerns centre on how the pipe and its fittings age, particularly when exposed to chlorinated water, high heat, or poor installation. Early plastic fittings and improperly crimped connections are frequent weak spots.

When failures happen, they can be sudden. A fitting may let go without warning and release water at full pressure until someone shuts it off. That is the main reason insurers and buyers ask about it.

Insurance questions

Many Canadian insurers ask whether a home has Poly-B. Some may raise premiums, apply conditions, or require replacement before they will offer coverage. Policies differ, and they change. If you have Poly-B, call your insurer and ask exactly what they require, and get the answer in writing.

Buyers often discover Poly-B during a home inspection, and it can come up in price negotiations. If you are on the buying side, read our guide to plumbing checks for older homes.

Replacement planning

Replacing Poly-B usually means running new supply lines, commonly PEX or copper, throughout the house. In finished homes, plumbers aim to route new pipe through closets, basements, and existing chases so that wall openings stay small. Repairs to drywall are normally a separate step.

A sensible plan looks like this:

1. Confirm the pipe type and how much of the house uses it.
2. Speak with your insurer about deadlines or conditions.
3. Get a written quote and a clear scope, including access openings.
4. Schedule the work and arrange for any patching afterward.
5. Ask for documentation of the new installation for your records.

Our polybutylene pipe replacement page explains how we approach it, and repiping covers whole-house replacement more broadly. If the water line from the street is also old, look at water line replacement too.

Owners who are not ready to replace everything right away can still lower the risk: know where the main shutoff is, fit leak alarms near the water heater and under sinks, and turn the water off before trips.