Pipe Identification Worksheet: Galvanized, Copper or Iron

Where to look

Most pipe in an older house is hidden, but a few places reliably show it: the water heater connections, under kitchen and bathroom sinks, behind the washer, at the front hose bib and, in raised-floor homes, the crawlspace.

Use a flashlight and a small magnet. Do not scrape painted pipe aggressively or disturb anything that looks fragile, and stay out of a crawlspace that is wet with sewage or has exposed wiring in water.

How to tell materials apart

Material	Look	Simple test	Usually used for
Galvanized steel	Dull gray, threaded joints	Magnet sticks; a light scratch shows silver	Older water supply lines
Copper	Reddish-brown or green-tinged, soldered joints	Magnet does not stick	Later supply repairs and repipes
Cast iron	Dark, heavy, large diameter, hub joints	Magnet sticks; sounds solid when tapped	Drains, waste and vent stacks
Vitrified clay	Reddish-brown glazed sections	Seen on camera or at excavations	Sewer lateral under the yard
ABS / PVC	Black or white plastic	Magnet does not stick; light weight	Newer drain repairs
PEX	Flexible colored tubing	Bends; crimp or expansion fittings	Newer supply repairs and repipes

Your house, location by location

Write what you find in each spot.
Location	Supply pipe material	Drain pipe material	Notes (rust, crust, leaks)
Water heater
Kitchen sink
Bathroom 1
Bathroom 2
Laundry
Front hose bib / main
Crawlspace

Also note

Any spot where one material connects to another.
Green, white or rust-colored crust at joints.
Pipe that has been painted, wrapped or patched.
Where the main drain leaves the house, and any cleanout cap.
Gas piping you see, without touching it.

Questions this worksheet helps answer

How much of my supply is still galvanized?
Where do old and new materials meet?
Is the main drain cast iron all the way to the foundation?
Do I need a camera inspection to see the lateral?

Common questions

Why does a magnet help?

Steel and iron are magnetic; copper and plastic are not. It is a quick way to separate galvanized from copper.

Can I see the sewer lateral myself?

Usually not. It is buried under the yard and is best seen with a camera inspection.

What if the pipe is painted?

Use the magnet and look at the joints. Threaded joints suggest steel; soldered joints suggest copper.

General information for Old Towne Orange, not a quote or professional advice. In an emergency, call 911.