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What Pipe Is In Your House, By Decade

The year a house went up tells you more about its plumbing than anything else you can see from the kerb. Here is the whole map, and how to check your own in about two minutes.

Every city page on this site opens with the share of homes built in each decade, because era is the best predictor we have of what is behind the drywall. This is the reference those pages point at.

Two systems run through a house and they are made of different things, fail differently and get replaced on different timelines. Supply is the pressurised pipe bringing water to fixtures. Drain, waste and vent is the gravity side taking it away. People say "the pipes" and mean one or the other without realising they are separate jobs.

The Map

Plumbing material by decade built, Northern Virginia
BuiltSupplyDrainWhat it does as it ages
Before 1940Galvanized steel, sometimes a lead service lineCast ironSupply bore closes with corrosion; lead service lines are a replacement job on their own terms
1940s-1950sGalvanized steel, copper toward the endCast ironFalling pressure and rust-coloured water; cast iron reaching the end of its service life
1960sCopper, galvanized still common earlyCast ironMixed-metal joints corrode where copper meets steel
1970sCopperCast iron giving way to PVCCopper pinholes; Orangeburg sewer laterals in anything pre-1972 deform and collapse
1980sCopper, and polybutylene from 1978PVCPolybutylene fails suddenly rather than seeping, which is what makes it different
1990sPolybutylene until 1995, then copper and CPVCPVCTail of the polybutylene window; early CPVC turns brittle
2000sCopper, CPVC, early PEXPVCLittle structural; water heaters and fixtures reaching a first replacement
2010s onPEXPVCHolding up well so far; failures are usually fittings or rodent damage in crawlspaces
What was standard at the time. It is not a guarantee of what is in a particular house, because plenty have been repiped since.

How To Check Yours In Two Minutes

Go to the water heater. The pipe coming out of the top is usually the easiest run in the house to see, and it is normally the same material as the rest of the supply.

  • Grey plastic, slightly flexible, often stamped PB2110. Polybutylene. Worth planning around.
  • Dull silver, threaded fittings, a magnet sticks to it. Galvanized steel.
  • Reddish brown metal, soldered joints. Copper.
  • Cream or tan rigid plastic, glued joints. CPVC.
  • Red, blue or white flexible tubing with crimp rings. PEX, and you have nothing to worry about.

What This Does Not Tell You

Era is a strong indicator and nothing more. Houses get repiped, additions get built in a different decade from the original, and a 1985 build may have used copper throughout because that is what the plumber had on the truck. Anyone who tells you what is in your walls without looking is guessing. This page is for narrowing down what to go and check.

Why We Publish This

Because the question comes up on nearly every quote, and because the honest version helps whether or not you call us. If you look at your water heater and find PEX, you have saved yourself a service call. We would rather be the people who told you that. Virginia Class A contractor license #2705131990, verifiable through Virginia DPOR.

Common Questions

How do I know if I have polybutylene?
Look at the pipe at your water heater or where a line enters the wall. Polybutylene is grey, slightly flexible and usually stamped PB2110. It was installed roughly 1978 to 1995, so the age of the house narrows it down before you even look.
Is polybutylene actually a problem, or is that oversold?
It is real. The failure mode is what makes it matter: it tends to go suddenly rather than weeping first, so the first sign is often water coming through a ceiling. That is different from copper, which usually gives you a stain and some time.
My house is from the 1960s. What should I worry about first?
The supply side. Galvanized steel corrodes inward and the pressure drops so gradually that people replace fixtures and showerheads for years before anyone checks the pipe. Cast iron drains of that age are a separate and slower conversation.
Can you just tell me over the phone?
We can tell you what is likely from the year built and the neighbourhood, which is usually enough to decide whether it is worth looking. We will not tell you what is in your walls without seeing it.
What is Orangeburg pipe?
A bituminised fibre sewer pipe used until about 1972. It softens and deforms into an oval rather than cracking, so the symptom is a line that backs up repeatedly and cables clear for a few months at a time. If a house is pre-1972 and the lateral has never been replaced, it is worth a camera.
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