The short answer
Start with the year the house was built. Builders used whatever pipe was standard at the time, so the build year is the best first guess at what’s behind your walls and under your yard. In Northern Virginia, where plenty of neighborhoods went up between the 1950s and the 1990s, that includes two kinds of pipe known to fail.
What’s usually in the walls, by decade
Swipe to see all columns →
Swipe to see all columns →
| House built | Water supply pipe | Drains and the sewer line |
|---|---|---|
| Before 1960 | Galvanized steel, sometimes copper | Cast iron inside; clay or Orangeburg to the street |
| 1960s and 1970s | Mostly copper | Cast iron, then plastic; Orangeburg into the 1970s |
| 1978 to 1995 | Copper, or gray polybutylene | Plastic (PVC or ABS) |
| After 1995 | Copper, then PEX from the 2000s | Plastic |
These are what builders commonly used, not a promise. Plenty of houses have been partly or fully repiped since, so a 1965 house can have PEX in one bathroom and the original galvanized everywhere else.
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The part most people don’t know
Some of the pipe in houses still standing was never built to last this long. Orangeburg pipe is tar paper pipe: wood fiber pressed together and soaked in coal tar pitch, laid as sewer line from about the 1940s, when metal was short during the war, into the 1970s. The North American Society for Trenchless Technology puts its life expectancy at about 25 years from experience, and it’s known to flatten and collapse. Pipe laid in the 1950s is well past 60 years old now. Our Orangeburg pipe guide covers what it looks like on a camera.
Polybutylene is the other one. It’s gray plastic supply pipe, often stamped PB2110, installed from 1978 to 1995. It failed often enough to end in a national class action settlement, and it tends to fail at the fittings without warning. If you have it, our polybutylene and repiping guide covers what replacing it involves.
How to check your own pipes
- Find where the water comes in. Usually the basement or a utility room, at the main shutoff valve. That’s the best place to see the supply pipe.
- Copper is the color of a penny, or dull brown with age.
- Galvanized steel is dull gray with threaded fittings, and a magnet sticks to it. It rusts from the inside, so low water pressure is a common sign.
- Polybutylene is gray plastic, sometimes with the PB2110 stamp. Look by the water heater too.
- PEX is flexible plastic, usually red, blue or white.
You can’t see the sewer line. It runs underground from the house to the street, and a camera is the only way to know what it’s made of and what shape it’s in. Our sewer camera inspection guide explains how that works, starting at the sewer cleanout. If you’re buying an older house, it’s worth doing before you close.
What goes down the drain matters more in an old pipe
Wipes labeled flushable are a problem in any sewer, and worse in an old one with rough joints and roots to catch on. The National Association of Clean Water Agencies estimates wipes cost utilities about $441 million a year in extra operating costs. In an Orangeburg or clay line they snag and build into a clog. Our list of what never goes down a drain is short and worth reading.
Have a plumber look
If you want to know what’s in your walls, the water heater flush is $99: we drain and flush the tank, check the anode rod and test the relief valve, then go through the house’s plumbing with photos, included. Our drain clearing is $99 for a clog up to the P-trap. Deeper drain or main sewer line work is a separate service, and we’ll give you that price before we start. Holding a big plumbing quote, like a repipe or a sewer line replacement? Our free second opinion sends a plumber to look at what you were quoted on, and you don’t owe us anything for looking.
Book it
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Questions people ask
How do I know what pipes are in my house?
Start with the build year, then look where the water comes in at the main shutoff. Copper is penny colored, galvanized steel is dull gray and a magnet sticks to it, polybutylene is gray plastic often stamped PB2110, and PEX is flexible red, blue or white plastic.
What years was polybutylene pipe used?
From 1978 to 1995. It’s gray plastic supply pipe that failed often enough to end in a national class action settlement.
What is Orangeburg pipe?
Sewer pipe made of wood fiber soaked in coal tar pitch, laid from about the 1940s into the 1970s. NASTT puts its life expectancy at about 25 years, and it’s known to flatten and collapse.
How do I know what my sewer line is made of?
A camera inspection. The sewer line runs underground from the house to the street, so a camera through the cleanout is the only way to see the pipe and its condition.
Are galvanized pipes bad?
They rust from the inside, which narrows the pipe and lowers water pressure over time. Galvanized steel in a house built before 1960 is usually near the end of its life.
