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Five Materials, and Where to Look at Them

Almost every water supply pipe in an American house is one of five things, and you can usually identify yours without tools in about five minutes.

The summary

Five materials cover almost every house: copper, galvanized steel, polybutylene, CPVC and PEX. They differ in color, in stiffness, and in the printing along the pipe. The place to look is wherever pipe is already exposed — a basement, a crawl space, or under a sink.

PipeRenew is a referral service, not a contractor. We connect homeowners with independent contractors. Contractors are required to hold whatever credential their state or municipality demands, and replacing a water distribution system is a permitted alteration nearly everywhere — ask to see the permit. We carry out no work, we sell no materials, we do not set prices, and we never charge homeowners anything — the contractors in our network pay us when we route them a call. Nothing here is legal advice about any claim.

Where to look

At the water heater, where several pipes are exposed together. At the main shutoff where the supply enters. Under sinks, where pipe emerges from a wall. In a basement, crawl space or garage ceiling, where runs are often visible for their whole length.

Look in more than one place. Houses are frequently a mixture, because somebody repiped part of it at some point and that is itself informative.

All five at once

The joint is the tell. Two of these are flexible plastic and the crimp rings look alike, which is why color matters: gray is polybutylene, red or blue or white is PEX.

The two metals

Copper is reddish-brown when clean and dull brown or green where it has aged. It is rigid, the joints are soldered, and a magnet does not stick to it.

Galvanized steel is dull gray, rigid, threaded at the joints rather than soldered, and a magnet sticks to it firmly. The threaded fittings are chunky and distinctive. It has its own page because what goes wrong with it is not what goes wrong with anything else.

The three plastics

Polybutylene is flexible, usually gray, with crimped metal or plastic fittings. The dates on it are exact, which makes it the easiest to place in time.

CPVC is rigid and usually cream or off-white, with solvent-welded joints. PEX is flexible, comes in red, blue and white, and is the common material in new work today.

Flexible gray with crimp rings and flexible red or blue are not the same thing, and that is the distinction worth getting right.

What the markings say

Plastic pipe usually carries printing along its length: the manufacturer, the material designation, a standard number and often a date code. It is faded on old pipe and worth a flashlight and a damp cloth.

A photograph of that printing is the single most useful thing you can have ready when you call anybody about repiping.

And what identification does not settle

It does not tell you the pipe has failed or will. Material is one input into a decision with several, and this site is not going to tell you that any material means you need a repipe.

Photograph the printing on the pipe before you call.It names the material and often the year, and it is the single most useful thing you can have ready. We route to contractors who do this work in your area, picked on the ZIP code you give, and you are never charged. Repiping is just what we write about — any plumbing work at all can be routed.

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