How to identify galvanized pipe (and why it matters)

Three materials, three looks

In a Montreal home built before 1970, the pipe visible in the basement is almost always one of three materials: lead, galvanized steel, or copper. Telling them apart takes less than a minute once you know what to look for.

Lead is dull grey and matte, and scratches easily with a fingernail or a coin — a lead pipe never has visible threading, unlike galvanized. It mostly shows up on the water service line, rarely inside the house. Galvanized is also dull grey, but rigid, threaded at the joints, and magnetic: a fridge magnet will stick to it. Copper turns reddish once you scratch the surface lightly, and a magnet won't stick to it at all.

The signs that don't lie

Galvanized corrosion happens from the inside, so the pipe can look fine to the eye while being nearly blocked. The most reliable signs: pressure that dropped gradually over several years rather than all at once, rusty or cloudy water at the very first draw of the morning, a marked flow difference between the ground floor and upstairs, and pipes that whistle when two taps run at once.

A single weak tap is often just a sand-clogged aerator — check that first before blaming the pipe. It's when the drop affects the whole house, or worsens over time, that galvanized pipe is the most likely suspect.

What's urgent, what can wait

A galvanized pipe that still works, even at reduced pressure, isn't an emergency in itself — it's a problem that worsens slowly. What's more urgent: an active leak at a corroded joint, pressure so low that a modern water heater or dishwasher can't function properly, or rusty water that persists past the first few seconds.

Lead, on the other hand, is worth addressing even without an obvious symptom, especially in a home with young children or someone who is pregnant. It's a question of exposure, not flow.

Replacing the private portion, coordinating the public one

The portion of the water service between the street and the service box usually belongs to the municipal network; the portion between the service box and the house is private. Replacing only the private portion fixes the flow problem indoors, but if the public portion is also lead or galvanized, the city may have its own replacement timeline — worth checking before starting work, to avoid digging up the same service twice a few years apart.

The table below summarizes the three materials you'll most often find.