Identifying the pipes in your house

Entry in Choosing pipe and trouble · Updated October 29, 2026 · Written by the Know Your Pipes editors from the sources listed under References

To identify pipes in your house, homeowners compare a few plain clues: color, how easily the surface scratches, whether a magnet sticks, the print line and the shape of the joints.^[1] Most supply pipe in US homes is lead, galvanized steel, copper or one of several plastics, and each leaves a distinct pattern.

Knowing the material matters for repairs, insurance questions and lead risk. Lead pipes are more likely in older cities and in homes built before 1986.^[2]

1 Where to look

The most useful place is the water service line where it comes into the building, often in a basement or crawl space near the water meter, or in a garage or utility closet.^[1] That short exposed stretch shows what the line from the street is made of. Other good spots are the pipes at the water heater, under kitchen and bathroom sinks, and behind access panels for tubs and showers. A house can contain several materials: a copper or plastic repair spliced into older steel is common, so checking more than one location gives a fuller picture.

Drain pipes are a separate system. The wide pipes that carry waste and vent gases are usually cast iron, black ABS or white PVC, and they do not tell much about the water supply.

2 Metal pipes

EPA's guidance for utilities describes three common metals and the simple tests that separate them.^[1]

Lead pipe is also often joined to other pipe with a "wiped" joint, a rounded bulb of lead at the connection.^[1] A magnet confirms the result because magnets react to steel and not to lead.^[1]

Galvanized steel pipe looks much like lead from a distance, which is why the magnet is the deciding clue. Under EPA's lead rules, a galvanized service line that is, or ever was, downstream of a lead service line is classed as "galvanized requiring replacement" and is handled like a lead line.^[1]

Copper tube is usually joined with soldered fittings. Hard copper is printed with a colored line that names its type, and all types are incised with the type and maker.^[3] The print line entry explains how to read that text.

3 Plastic pipes

Plastic supply pipe is smooth and comes in several colors.^[1] Color is a useful first clue, but the print line settles the question.

• PEX is flexible tubing, often red, blue or white, and sometimes left natural (translucent). The colors are a convenience for installers; model plumbing codes do not require red for hot or blue for cold, and all colors meet the same requirements.^[4] Its print line includes a "PEX" code with four digits.^[4] See PEX pipe.
• CPVC is rigid and cream or tan, made in copper tube sizes for hot and cold water.^[5] See CPVC pipe.
• PVC is rigid and white for Schedule 40 and dark gray for Schedule 80.^[5] One pipe maker lists PVC as a pressure material for carrying drinking water up to a building, with CPVC the one used for drinking water inside it.^[5]
• ABS is black, used for drains and vents, and one maker notes it is found more often in the West.^[5] See ABS pipe.

Plastic pipe that does not match any of these, or that carries an unfamiliar brand name, may be a retired material such as polybutylene or Kitec; their entries describe how to recognize them.

4 Limits of a visual check

A visual check identifies the pipe, not the water. EPA notes that testing drinking water is the only way to confirm whether lead is present, and that lead can come from plumbing materials and faucets even when the service line is not lead.^[6] Among homes without lead service lines, the most common sources are brass or chrome-plated brass faucets and plumbing joined with lead solder.^[2] EPA's guide points readers to certified drinking-water laboratories for that test.^[6]

Pipes hidden in walls, slabs and ceilings cannot be seen without opening them, and the visible stretch may not match what is buried. Where a utility is building its service line inventory, it may record the homeowner's findings or send staff to do the same scratch and magnet checks.^[1]