Guide: old supply lines
Galvanized Steel Pipes: Problems and Replacement
Galvanized steel water pipe was common in older homes. It rusts from the inside out. Here is how to spot it and what to do.
- Grey, dull metal pipe with threaded fittings
- A magnet sticks to it
- Threaded joints at every connection
- Often found near the water meter, in basements and under sinks
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What galvanized pipe is
Galvanized pipe is steel coated with zinc to slow corrosion. It was widely used for water supply in homes built before the 1960s. With time the zinc coating is used up and the steel corrodes from within, narrowing the pipe and staining water.
How to identify it
- Grey, dull metal pipe with threaded fittings
- A magnet sticks to it
- Threaded joints at every connection
- Often found near the water meter, in basements and under sinks
Problems it causes
- Low pressure. Rust builds up inside, reducing flow.
- Discoloured water. Brown or rusty water, especially after the water has been off.
- Leaks. Threaded joints corrode and leak.
- Lead concerns. Galvanized pipe downstream of lead pipe can trap lead particles.
What to do
If only a few sections remain, replace them as they fail. If most of the house is galvanized, plan a full repipe. It is often easiest during renovations. See repiping, low water pressure causes and leak detection.
Questions we get about this
Can I replace just the worst sections?
Yes, as a stopgap. Expect rust from older sections to keep affecting pressure and colour until the rest is replaced.
Does galvanized pipe affect water taste?
Rust can give water a metallic taste and a tint, especially first thing in the morning or after the water has been off.