The pipes inside your walls: a guide to NoVA housing by decade

The decade your house was built tells you a lot about the pipes inside its walls and how they tend to fail. In Northern Virginia, where so much of the housing stock dates from the 1950s through the 1980s, that's worth knowing before a leak makes the decision for you.

Before 1960, homes commonly got galvanized steel supply lines and cast iron drains. By the 1960s and 1970s, copper was standard. From 1978 to 1995, many homes got polybutylene. The 1990s and 2000s brought a mix of copper and CPVC, and since the 2000s, PEX has become increasingly common.

Before 1960: galvanized steel and cast iron

Homes built before 1960 were commonly plumbed with galvanized steel supply lines and cast iron drains. These materials seemed bulletproof at the time. Six decades later, they're showing their age in older parts of Arlington and Alexandria.

Galvanized steel rusts and collects mineral buildup from the inside out. The first thing you notice is weak flow at fixtures that keeps getting worse, until a strong shower becomes a trickle.

Cast iron sewer lines crack and separate over time, especially in NoVA's clay soil. Tree roots find those cracks and work their way in, turning small leaks into backups.

Red flags in pre-1960 homes:

• Rusty or discolored water
• Weak flow that keeps getting worse
• Frequent drain backups
• Rust stains around fixtures

1960s–1970s: copper supply lines

By the 1960s, copper was the standard supply material, and many NoVA homes from this era still have their original copper. Copper is long-lasting and reliable.

Over time, though, water chemistry and other factors can contribute to pinhole leaks. Our local water is disinfected with chloramine, which is part of that picture. Pinhole leaks often start small and grow, and you may see a water stain on a wall or ceiling before you ever see the leak. Older copper joints may also have been made with lead-based solder.

Many homes from this era paired copper supply lines with cast iron drains. Your supply lines might be fine while the sewer line needs attention.

1978–1995: the polybutylene problem

From 1978 to 1995, builders used polybutylene, a gray plastic pipe that seemed like the future of plumbing. It was quick and easy to install and marketed as lasting forever.

It didn't. Polybutylene breaks down from the inside when exposed to the chlorine and chloramine disinfectants used in municipal water. It can fail suddenly, with little warning, and the damage can be severe.

If your home was built in this window, polybutylene replacement belongs on your radar. Some insurers decline or surcharge homes that still have it. For the full picture, see our post on polybutylene pipes in NoVA homes.

1990s–2000s: Copper and CPVC

The 1990s brought a mix of copper supply lines and CPVC (chlorinated polyvinyl chloride), the cream-colored plastic pipe.

CPVC was an improvement over polybutylene, but it has its own issues. Over time it can become brittle, and the fittings can crack and leak suddenly.

Copper from this era generally performs well, though pinhole leaks remain possible as these pipes pass the 30-year mark.

2000s to today: PEX

Since the 2000s, PEX (cross-linked polyethylene) has become increasingly common in residential plumbing. Many newer homes in Loudoun County have it throughout.

PEX is flexible, resists scale buildup, and handles disinfectants well. It tolerates freezing better than rigid pipe, though it isn't freeze-proof. The fittings are mechanical rather than glued or soldered, which makes repairs straightforward. When an older home needs new supply lines, PEX repiping is often the best replacement choice.

What our technicians look for

Our technicians can usually tell what you have from an exposed run of pipe under a sink or near the water heater:

• Galvanized steel: dark gray, threaded connections, heavy
• Copper: reddish-brown metal, soldered joints
• Polybutylene: gray plastic, often stamped "PB"
• CPVC: cream or off-white plastic
• PEX: flexible tubing, often red for hot and blue for cold

On the drain side, cast iron is dark and heavy, and PVC is white plastic.

Knowing the era changes the plan. A 1978 McLean home might need full polybutylene replacement, while a 1950s Arlington colonial might only need its galvanized supply lines updated. Our diagnostics team can camera your sewer line and pressure-test your supply system so you know exactly what you're working with.

We're a family-owned company with decades of combined hands-on experience in NoVA homes of every era, licensed, bonded, and insured, and we give a written, upfront quote before any work begins. To find out what's behind your walls, call (703) 508-3088.