Plumbing notes · when buying an older home

Telling lead and galvanized pipe apart in an older house

Some houses built before the middle of the last century still draw water through a lead service, and plenty from that era carry threaded galvanized steel indoors too. Both deserve identifying, for different reasons: lead because of what it can add to drinking water, galvanized because of rust and dwindling pressure.

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A fire hydrant in the middle of a building under construction — From the almanac guide on lead and galvanized pipes.

Spotting lead

Lead is matte grey and soft, and gives a dull thud instead of a ring when tapped. Draw a key gently across it and a bright silver streak appears. Magnets ignore it. Scratch-test the stub between foundation wall and meter.

Spotting galvanized

Galvanized is grey steel joined with threaded fittings, and a magnet clings to it. Rust weeping at joints and feeble pressure are typical signs of age.

What to do about it

Flush the cold tap before drinking if your service may be lead
Read Halton Region’s information on lead service replacement
Plan galvanized repiping ahead of renovations
Replace corroding mixed-metal joints

One more thing

If testing or inspection suggests lead, the most effective solution is replacing the service line. In the meantime, running the tap before drinking, using cold water for cooking and drinking, and using a certified filter can reduce exposure.

Galvanized pipe does not pose the same health concern as lead, but it corrodes from the inside and eventually restricts flow. Replacing it is usually a matter of when, not if.

Some older homes have a mix of lead, galvanized and copper. Understanding what you have helps you plan replacements in a sensible order.