The Truth About Cast Iron Plumbing.

If you own a home built before the 1970s—or are thinking about buying one—there’s a good chance the plumbing system includes cast iron pipes. While cast iron was a go-to material for decades thanks to its strength and durability, time hasn’t been kind to it. And if it's still quietly running beneath your home, it could be a ticking time bomb.

Here’s what you need to know about cast iron plumbing and why a thorough inspection is essential in older homes.

What Age Homes Typically Have Cast Iron Pipes?

• 1920s–1970s: Cast iron was the gold standard for drain, waste, and vent piping. It was durable, fire-resistant, and relatively easy to install.

• 1975(or so) onward: Homes built after the mid-70s more commonly used PVC (polyvinyl chloride), a lighter, corrosion-resistant alternative that remains common today.

So if your home was built before 1975, there’s a very strong chance cast iron is running through your plumbing system—and it may be nearing the end of its life.

Why Cast Iron Plumbing Is a Problem Now

Cast iron has a natural lifespan of about 50 to 70 years, depending on environmental factors like soil conditions, water quality, and maintenance. That means:

• Homes built in the 1950s are now 70+ years old

• Even homes from the late 60s and early 70s are approaching the danger zone

The problem? Cast iron corrodes from the inside out, meaning by the time you notice symptoms, the damage is often advanced. Cracks, leaks, and even total pipe failure can happen without warning.

Signs of Failing Cast Iron Pipes

• Recurring drain clogs or slow drainage

• Water stains on walls or ceilings

• Rotten egg or sewer smells in your home

• Foundation cracks or settling due to underground leaks

• Mold or mildew growth

• Unusually lush patches of grass (if a buried pipe is leaking)

These signs could mean you’ve already got a compromised system—one that's leaking water (or worse, sewage) and possibly damaging your home.

Why Plumbing Inspections Are Essential for Older Homes

A plumbing inspection—especially one that includes a camera scope of your sewer lines—can reveal the condition of your cast iron pipes. This gives you:

• Clarity on whether a full or partial replacement is needed

• Time to plan financially before disaster strikes

• Negotiating power if you’re buying a home with old plumbing

• Peace of mind knowing your home is safe and dry

Inspections are relatively quick and non-invasive, but they can save tens of thousands in unexpected repairs and water damage.

Cast Iron Replacement: What’s Next?

If your cast iron pipes need replacing, modern solutions like PVC or HDPE piping offer long-lasting performance, resistance to corrosion, and easy installation. While replacing old plumbing isn’t cheap, it’s often more affordable (and far less stressful) than dealing with emergency sewer backups or foundation damage down the line.

Old homes are beautiful, but what’s behind the walls matters just as much as that Austin bungalow charm and hardwood floors. If your home was built before 1975, do yourself a favor and schedule a plumbing inspection. Cast iron doesn’t last forever—and knowing where your plumbing stands is the first step in protecting your investment.

Alan Galinsky

Realtor at Open House Austin

I’ve lived in Austin for 19 years and love helping people find the right home through a mix of problem-solving and personal connection. When I’m not working, I’m likely watching movies, exploring North Loop, or hanging out with my dog Charlie. Connect with me here.