Primer · Old pipe

Galvanized and Poly-B Pipe Explained

Two materials worry home buyers and insurers more than any other supply pipe: grey galvanized steel and grey plastic polybutylene. Here is how to tell what you have.

Plain steps you can do yourself, safely
Clear signs for when to stop and call
Written for Newmarket houses and water
A plumber on the phone if it goes sideways

What goes wrong in the pipes

Galvanized steel was common in Ontario homes built before about the 1960s. It rusts from the inside, and the scale narrows the pipe until pressure drops and rusty water appears. Polybutylene, often called Poly-B, was used from the late 1970s into the 1990s. It can become brittle and its fittings can fail without warning. Many insurers ask about both, and some limit coverage until they are replaced.

Have these on hand

Flashlight
Adjustable wrench
Towels and a bucket
Our number on the panel door

Step by step: identify your pipe

Find where the water enters. Look at the pipe near the meter and the main shut-off.
Check galvanized: dull grey metal with threaded joints. A magnet sticks to it. A scratch shows silver steel underneath.
Check Poly-B: flexible grey plastic, often stamped PB2110, with crimp rings of copper or plastic fittings.
Look at the branches. Many houses had partial repairs, so inspect pipe by the heater, below vanities and behind the washer.
Note the condition. Rust stains at joints, low pressure upstairs or discoloured water are warning signs.

Mistakes that turn a small repair big

Patching one leak in galvanized pipe and expecting the rest to hold.
Joining copper directly to galvanized without a dielectric fitting, which speeds corrosion.
Assuming grey plastic is safe because it has not leaked yet.
Forgetting the main service line, which may also be galvanized or even lead in very old homes.

When to put the tools down and call

Call when you buy an older house, when an insurer asks, or when you see leaks or falling pressure. Replacement usually means running new PEX or copper through the house in stages, with small access holes rather than tearing out every wall. Read about our water line replacement and burst pipe repair services. While the basement is open, consider your backwater valve.

Asked on site

Is Poly-B illegal?

No, but it is no longer installed, and many insurers treat it as a risk. Check with your insurer about their requirements.

Can galvanized pipe be cleaned out?

Not in a lasting way. The rust is part of the pipe wall, so replacement is the real fix.