Zinc-coated steel water pipe, standard in homes built roughly before 1960. Its serviceable life is on the order of 40–60 years (averaging around 50), and once the protective zinc wears through, the steel underneath corrodes and scales up from the inside, narrowing the bore like a clogged artery.
$4,000–12,000 to repipe (partial fixes possible)Address soonPlumbing
Why it matters
In most homes that still have it, galvanized supply pipe is near or past end of life. The tells are low water pressure (worst upstairs or when two fixtures run at once), rusty or discoloured water after the house has sat, and a rising risk of pinhole leaks. Corrosion can also trap small amounts of lead at the scale where galvanized pipe once connected to a lead service line. It's less of an insurance flag than poly-B or lead, but it's a real, easy-to-verify cost worth pricing into an offer.
How to spot it
Dull grey threaded steel pipe (screwed joints, not soldered like copper); it's magnetic — a fridge magnet sticks, which is the quick way to tell it from lead (lead is non-magnetic); rust staining at the threads; and weak flow when you open several taps at once.
What it costs
Roughly $4,000–12,000 to repipe a house; some buyers do it in phases as walls are opened.
What to do
Address soon. Have a licensed plumber confirm the material and how much remains, run the taps during your walkthrough to feel the pressure, and budget for a repipe.
Education and triage, not a home inspection. Casaroo flags galvanized pipe and weak flow from your photos and notes — a licensed plumber confirms how much life is left.
Common questions
What is Galvanized steel supply piping?
Zinc-coated steel water pipe, standard in homes built roughly before 1960. Its serviceable life is on the order of 40–60 years (averaging around 50), and once the protective zinc wears through, the steel underneath corrodes and scales up from the inside, narrowing the bore like a clogged artery.
Why does it matter for home buyers?
In most homes that still have it, galvanized supply pipe is near or past end of life. The tells are low water pressure (worst upstairs or when two fixtures run at once), rusty or discoloured water after the house has sat, and a rising risk of pinhole leaks. Corrosion can also trap small amounts of lead at the scale where galvanized pipe once connected to a lead service line. It's less of an insurance flag than poly-B or lead, but it's a real, easy-to-verify cost worth pricing into an offer.
How can I spot it?
Dull grey threaded steel pipe (screwed joints, not soldered like copper); it's magnetic — a fridge magnet sticks, which is the quick way to tell it from lead (lead is non-magnetic); rust staining at the threads; and weak flow when you open several taps at once.
How much does it cost to fix?
Roughly $4,000–12,000 to repipe a house; some buyers do it in phases as walls are opened.
Lifespan figures are industry estimates and vary with water chemistry; a licensed plumber confirms condition. Casaroo flags, it does not inspect.
Last reviewed 2026-06-27.
Casaroo reviews each guide against current pricing, code, and insurer practice. Cost ranges are 2026
estimates that vary by region, size, and access — confirm specifics with a licensed professional.