What Kind of Pipe Do I Have? Copper, PEX, PVC, Galvanized or Lead

Hold a magnet to the pipe: it sticks only to steel, which means galvanized water pipe or black iron gas pipe. Then scratch it gently with a coin or key: copper shows a penny color, and lead shows shiny silver.

Is the pipe metal or plastic?

Look where it comes through the wall or floor.

MetalCopper-colored, gray, silver or black PlasticWhite, cream, gray, red, blue or black

Is it flexible tubing or rigid pipe?

Flexible tubingBends in long curves Rigid pipeStraight lengths with glued fittings

What color is it?

Cream or tanOff-white WhiteBright white GrayLight or dark Another colorBlack, blue or something else

Where does it run?

Inside the houseTo faucets, fixtures or the water heater In from the streetThe line that brings water to the house

Does a magnet stick to it?

Any fridge magnet works.

Yes, it sticksSteel or iron NoCopper, brass or lead

Scratch it gently with a coin or key. What color shows?

Penny colorCopper-orange Shiny silverAnd the pipe is dull gray and soft GoldYellow, like brass hardware

Where does the pipe go?

Follow it from where you tested.

To faucets or fixturesIt carries water To a gas valve or applianceA stove, furnace, dryer or the water heater’s burner Can’t tellIt disappears into a wall

You most likely have

CPVC pipe

Rigid cream or tan plastic with glued joints, made for hot and cold water (ASTM D2846) up to 180°F.

On the package: CTS CPVC, ASTM D2846

Copper-tube-size CPVC also takes standard push-to-connect fittings.

Next

SharkBite fittings Join it to another pipe

You most likely have

PVC pipe

Rigid white plastic with glued joints.

PVC brings water up to a house and carries drain water. For water lines inside, codes list CPVC, PEX or copper instead.
It’s limited to 140°F, so it isn’t used for hot water lines.
Print reading “ASTM D1785” marks pressure pipe, and “ASTM D2665” or “Not for Pressure” marks drain pipe.

Next

Is it 1/2" or 3/4"?Garden hose to PVC Join it to another pipe

You most likely have

Read the print

Gray plastic can be several things. Schedule 80 PVC is dark gray, and some CPVC is light gray.

If the print names PVC, CPVC or PEX, that’s your pipe.
If there’s no print, or it names none of those, ask a plumber. Older homes can have polybutylene, a plastic pipe from the late 1970s and 1980s.

You most likely have

Look for its name on the pipe

Plastic pipe is printed with its type and the standard it meets, such as PEX, CPVC or PVC with an ASTM number.

If nothing’s printed, a plumber can tell you what it is.

You most likely have

PEX tubing

Flexible plastic in white, red or blue, printed with “PEX” and its standards (ASTM F876/F877).

Red PEX is sold for hot lines and blue for cold.
Its joints use crimp or clamp rings, or expansion fittings, with no glue or solder.

Next

Is it 1/2" or 3/4"?SharkBite fittings Shutoff valve for PEX Join it to another pipe

You most likely have

A plastic service line

Plastic service lines are usually white or gray, sometimes blue or black. The print tells you if it’s PEX or polyethylene (PE).

Plastic adds no lead, but lead can still be in faucets or old solder further along.

You most likely have

Copper pipe

A penny color where scratched, and a magnet won’t stick.

Check the printed color on rigid copper. Green is Type K, blue Type L and red Type M. Yellow (DWV) is drain pipe.
Joints are soldered, or made with compression, flare, press or push fittings.

Next

Is it 1/2" or 3/4"?SharkBite fittings Shutoff valve for copper Join it to another pipe

You most likely have

Possibly lead

Lead is dull gray and soft, turns shiny silver when scratched, and a magnet won’t stick. It often curves and swells into a bulge at the joint.

Contact your water utility or state. Some programs pay for water testing or for replacing lead lines.
Have the water tested, and have a plumber confirm before you connect anything to it.

EPA and the CDC agree there’s no known safe level of lead in a child’s blood.

You most likely have

Brass

Gold where scratched, threaded at the joints, and not magnetic.

On the package: Pipe thread (NPT) in its size, e.g. 1/2 in. MIP

Measure across the threads to find its size. 1/2" pipe thread is 0.840" across, and 3/4" is 1.050".
Pipe-thread fittings of the same size screw on, with tape or sealant on the male threads.

Next

Pipe thread size

You most likely have

Galvanized steel

Magnetic, hard to scratch, and threaded at every joint.

As it ages it rusts and clogs with minerals. Rust-colored water and weak flow are signs.
If it was ever connected below a lead service line, ask your water utility about testing. Lead can cling inside it.

Next

Pipe thread size Join it to another pipe

You most likely have

Black iron gas pipe

Gas lines are black iron or steel, magnetic and threaded like galvanized water pipe.

Don’t loosen or cut it. Gas work is for a licensed pro.

You most likely have

Steel, for gas or water

A magnet sticks to both galvanized water pipe and black iron gas pipe. Trace it from where it enters the house or to the appliance it feeds.

Until you know, treat it as a gas line and leave its joints alone.

Plastic pipe is told apart by whether it bends, its color, and the print on it.

Metal pipe: magnet and scratch

What kind of water pipe

Telling metal water pipe apart
Pipe	Magnet	Scratched	Joints
Copper	Doesn’t stick	Penny color	Soldered or fitted, no threads on the pipe
Lead	Doesn’t stick	Shiny silver	No threads; often a bulge at the joint
Galvanized steel	Sticks	Hard to scratch, stays gray	Threaded
Brass	Doesn’t stick	Gold	Threaded

whatadapterfor.com

Test close to where the pipe comes through the wall or floor. All you need is a coin or key and a fridge magnet.

Read the print

Copper: rigid copper is stamped with its type and printed in a color: green for Type K, blue for Type L, red for Type M (all three for water), yellow for DWV (drains).
PEX: the print includes “PEX”, the size and the standards, such as ASTM F876/F877.
CPVC: cream or tan, made to ASTM D2846, the standard for hot and cold water lines.
PVC: “ASTM D1785” is pressure pipe and “ASTM D2665” drain pipe; some is printed with both. Foam-core drain pipe is printed “Not for Pressure”.

PVC or CPVC?

They look alike apart from the color, and both are glued. CPVC (cream or tan) is rated for hot and cold water up to 180°F. PVC (white, or dark gray for schedule 80) stops at 140°F. It carries water up to the house, and drain water. The plumbing code’s list of pipe for water lines inside a house includes CPVC, PEX and copper, but not PVC.

Before you work on it

Lead: there’s no known safe level of lead in a child’s blood. Lead pipe is most likely in older cities and homes built before 1986. Have the water tested, and contact your water utility or state, some of which help pay for testing or for replacing lead lines.
Galvanized pipe that was ever connected below a lead service line can hold lead and release it into the water.
Gas: black iron or steel pipe carries gas. Follow a magnetic pipe to see where it goes before you loosen anything.
Polybutylene, a plastic water pipe sold in the late 1970s and 1980s, was the subject of class-action lawsuits over alleged leaks. If you can’t tell what a plastic pipe is, have a plumber look.

Know the pipe, need the size?

Is it 1/2" or 3/4"?

Common questions

How can I tell if my water pipe is lead?

Lead pipe is dull gray and soft. A gentle scratch with a coin turns it shiny silver, and a magnet won't stick to it. If yours matches, contact your water utility and have the water tested.

Is gray plastic pipe polybutylene?

Not necessarily. Schedule 80 PVC is dark gray and some CPVC is light gray. Check the print, and if it doesn't name the pipe, ask a plumber.

Can PVC be used for hot water?

No. PVC is limited to 140°F; CPVC, PEX and copper are the usual pipes for hot water lines.

What do the colors printed on copper pipe mean?

They name the tube type: green is Type K, blue is Type L and red is Type M, all used for water. Yellow marks DWV, used for drains.

Where we get our information from

The sizes on this page come from published standards and the makers’ own documents. Checked against published data from US EPA, Swagelok, Uponor, Charlotte Pipe and National Bureau of Standards (plus 8 more).

See all 19 sources

National Bureau of Standards, Handbook H28 (1957) Part II: Table VII.2 (American Standard taper pipe threads, NPT) and Tables X.1–X.3 (hose coupling threads, NH)
Swagelok, Thread and End Connection Identification Guide (MS-13-77)
Swagelok, Thread Sealants catalog (MS-14-01): PTFE tape, how to apply
SharkBite (Reliance Worldwide), SharkBite PEX Installation Guide (2021): fits copper, CTS CPVC and PEX in any combination
US EPA, Customer Guide for Identifying Service Lines (2024): scratch and magnet tests, galvanized downstream of lead
US EPA Science Matters, EPA Researchers Share Approaches to Identify Lead Service Lines
US EPA, Basic Information about Lead in Drinking Water
US EPA, Protect Your Tap: A Quick Check for Lead
DC Water, Water Service Pipe Material Identification
Waterford Utility Commission (Connecticut), Water Service Line Material Identification
HUD, Residential Rehabilitation Inspection Guide (2000): water supply piping, fuel supply
Copper Development Association, The Copper Tube Handbook (2026): identification, color codes, joining
Uponor, PEX Piping Systems Installation Guide, seventh edition (2025): ProPEX expansion fittings, pipe colors, copper and threaded adapters, no soldering within 18" of PEX
Uponor, PEX-a Installation Guide, second edition (2024): ASTM F876/F877, red and blue pipe (copy on a retailer server)
Charlotte Pipe, Plastics Technical Manual (2026): PVC and CPVC colors, standards, temperature limits, Not for Pressure print, plastic-to-metal threads and brass transition fittings
Charlotte Pipe, FlowGuard Gold CTS CPVC submittal and product page: ASTM D2846, 180 F, solvent cement
Michigan Administrative Code R 408.30727 and R 408.30729: Tables 605.4 (water distribution) and 605.3 (water service pipe)
ASTM D3309-96a, Polybutylene (PB) Plastic Hot- and Cold-Water Distribution Systems (historical standard)
Tennessee Court of Appeals, No. W2004-01777-COA-R3-CV (2005): polybutylene plumbing class action (copy on FindLaw)

General guidance from manufacturer and standards data. Parts vary by brand, so check the size printed on the package against what you measured. For gas lines or anything inside a wall, use a licensed plumber.