How Long Do Cast Iron Pipes Last? [& Other FAQ Answered]

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What Is Cast Iron? Cast Iron is a metal alloy produced from a mix of carbon. Iron, and silicone.

Cast Iron cannot be pressed or hammered into shape. This is why it is malleable. So, it’s cast in a mold before being installed.

Cast Iron pipes last between 80-100 years and are built to withstand high volumes of water pressure.

But, like galvanized steel, cast iron piping has been found to be susceptible to leaks from the joints and rust over time.

The most common replacement for cast iron piping is PVC piping. PVC piping is easier to work with and is lightweight.

Other alternatives such as PEX is still quite new, and have proven to perform better than cast iron.

In the coming sections, I will explain whether you should purchase a house with cast iron pipes or not, how to know if you have cast iron pipes, the Advantages, and disadvantages of cast iron pipes, and how much it costs to replace cast iron pipes with PVC or PEX.

When Was Cast Iron Plumbing Used?

Cast iron plumbing was first used in the 1970s.

Does Your House Have Cast Iron Drain Pipes?

Most homes constructed before the 1970s were made with cast iron for sewage and water pipes.

So, if the home you currently live in now was built far back then it means you may already have a leak. Since the pipes have reached their effective lifespan.

Remember, cast iron can last 50 to 100 years but a home built in the ‘20s and ‘30s is nearing its end.

Keep in mind that cast iron can last its whole lifespan but many circumstances can affect its longevity.

Below are the advantages and disadvantages of cast iron drain pipes.

Advantages of Cast Iron Drain Pipes (How Modern Still Works)

  • You enjoy 50 to 100 years of service life.
  • With proper care, some have been known to exceed 100 years. However, factors such as tree roots, water quality, weather, and types of soil could reduce their lifespan.
  • They can withstand high pressure and heavy loads
  • Cast iron is silent as the water rushes through it.
  • Cast iron hardly vibrates since it is very dense. So, it creates less noise than PVC. I was able to hear the sound when I placed my ear against the pipe. PVC on the other hand isn’t; dense and will rattle and shake as water passes through. You can even hear your kids pipes as they flush up the stairs.
  • Cast iron can be used as pans and pots. With proper care, they hardly go bad.
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Modern Cast Iron Drain Pipes

New cast iron pipes are better than ever. They feature rubber couplings and stainless-steel band clamps to make leak-proof connections.

That means you can do adjustments to curves and bends (fitting angles) after installation. With PVC, you only have seconds to adjust once it’s glued.

Old cast iron was a pain in the butt to install since it involved melted lead ingots and oil-soaked ropes.

However, modern cast iron is spun while being molded (spun cast), so the pipe wall thickness is more consistent and produces a denser iron.

Disadvantages of Cast Iron Drain Pipes

Cast iron was made to last with proper maintenance. Sadly, there’s no way to truly care for pipes that run inside walls or underground.

So, over time, issues like the following may rise up:

  • Tree Attack

Tree roots shooting out of the ground upward can destroy pipes such as cast iron and terracotta.

  • Leaks

In your pipes, leaks can be caused by damage or crack from sulfuric acid (or other corrosive materials like drain cleaners).

  • Odor

Sewer systems are made to be airtight.

Can you smell sewage? That is a clear sign of a cracked sewer pipe.

That is bad for your health and the environment. Inhaling sewer gas for too long can lead to health problems.

  • Backups

Clogs and slow draining are other signs of a failing or failed pipe.

Avoid using cleaning products that contain sulfuric acid since that is damaging to cast iron pipes.

  • Mold

Mold will grow if there is increased humidity in your home.

Guess what? A cracked pipe will create the perfect ecosystem for mold to grow and thrive.

You certainly do not want that. Things can quickly get messy from that point onward.

  • Strange lawn signs

Leaking sewage serves as a fertilizer and your grass can show signs of extreme growth or a lush green color.

So, if you notice puddles of sewage or water waste in your yard, you can ve certain a pipe is cracked and leaking.

Your soil can sink, develop strange bumps, or even gutter due to soil dissipating.

  • Cracks

Leaking pipes can scatter your foundation and cause floors, walls, or ceilings to crack.

  • Rodents or insects

Insects and rodents (like cockroaches, palmetto bugs, and flies) can find their way through even the tiniest of cracks, and make your home their place of abode and breeding.

Pest control can kill the current invaders but more will come if the root of the problem is not handled.

Should I Buy a House with Cast Iron Pipes?

Yes, you can purchase a house with cast iron pipes. But first, have a plumber come do an inspection on the home before making payments.

The plumber can do one or all of the following:

  • A building inspection – to estimate how much life is left for the pipes.
  • A sewer scope – The use of a thin camera threaded along the lines to look for any issue.
  • Visual assessment – A plumber can also inspect the pipes to see how long they think the cast iron pipes will last

ALSO SEE: How Long Do Brass Pipes Last?

Does Insurance Cover Cast Iron Pipes?

Sometimes, yes. Other times, No!

Some certain aspects of cast iron replacement might be covered by insurance. So, it is important to work with the seller where possible to ensure the plumbing is in good condition before the sale is closed.

If plumbing issues are found during the home inspection, the price of the home can also be reduced.

How Do I Know If My Cast Iron Pipes Are Bad?

The main signs of a bad cast iron pipe are:

  • Water discoloration
  • Poor water pressure
  • Leaks
  • Ground sagging
  • Slow drainage
  • Pooling of wastewater
  • Areas of the yard that are growing better than others
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I’ll provide a brief description of what they look like and why they indicate that the cast iron plumbing may need to be replaced or repaired below.

  • Water discoloration

A blockage in the lines will cause your tap water to produce a yellowish or brown color of the water. The inside of a cast iron pipe can rust a bit, which creates a rough surface.

The rough surface holds on to tiny particles in the water and leads to a build-up over time. Some of these buildups then begin to break off and become suspended in the water, giving it a fun color.

Plus, if it’s partially blocked with rust, part of the rust will wash off into the water and give it an orange tint.

  • Leaks in Cast Iron Piping

A solid sign of pool leaks is pools of water underneath the pipes.

You may also see droplets of water forming at certain points along the pipes. These typically need to be repaired very soon as they can rot the wood.

It’s difficult for them to dry in colder months, leading to a bigger and bigger puddle of water.

  • Ground Baggage

If areas of the ground surrounding the house are lower than other areas, then it could very well mean you have a pipe burst or leak in your home.

In most cases, the excess water can cause the ground to sag, it’s also perfectly natural for the ground to sag in certain places. So, to know for sure, you’d need to do a sewer scope.

  • Slow Drainage in Cast Iron Pipes

When the pipes are clogged leading away from the house, the water will take longer to go down the drain.

You’ll also observe that the sinks will slowly begin to fail to drain at the usual speed, and you might get pools of water on the exterior of the house near the drains.

  • Pooling of Waste Water

When the pipe suffers a leak or rupture, the wastewater can create small puddles in the yard and be wet even when the rest of the yard is dry, and it hasn’t rained recently.

  • Areas of the Yard That Are Growing Better Than Others

Sewage is a natural compost for the garden, so when there’s a leak or rupture in the pipes leading away from your home, it can have a positive effect on the plants in your yard.

It’s very identifiable if there’s also a foul smell to the area that’s growing better than others.

  • Moldy walls

A mold on the walls of your bathroom or kitchen is a good indication of a cracked cast iron pipe.

It doesn’t require lots of moisture for mold to begin growing. Even the tiniest leak will cause a slight increase in the humidity levels. This can be the result of the slightest crack, which can lead to mold growth.

  • Indentations in Your Pavement or Lawn

If you see slumps or divots in the pavement or grass on your property, it’s time to investigate.

The water from leaking drainage pipes can form pools under your driveway or lawn.

If this goes on long enough, you will notice that certain areas will begin to dip or sag, forming indentations.

So, if you spot anything like this on your property, call in a plumber immediately.

How Long Do Cast Iron Pipes Last

How to Tell If You Have Cast Iron Pipes

  • The pipe will have a dull black finish
  • Cast iron pipes have unique bumps on each of the joints that aren’t present in PVC pipes.
  • Tao on the bumps and they should produce a dull metallic sound.
  • Copper pipes also have joints similar to cast iron, but copper pipes have a distinctive red/orange color.
  • Take some photos and post them where you can ask for people’s opinions.
  • If all else fails, you can get a plumber in to take a look at them. But, they’ll likely be happy to tell you free of charge or at a low cost if you send them photos of the pipes.
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Cost To Replace Cast Iron Pipes With PVC           

In total, it will cost roughly $10,000 to $20,000 to replace all cast iron plumbing with PVC pipes. Repairs of cast iron piping typically involve replacing cast iron with PVC. Repairs to small sections of cast iron piping can range from $300 to $1000.

How Much Does It Cost to Replace Cast Iron Pipes?

In total, it will cost roughly $10,000 to $20,000 to replace all cast iron plumbing with PEX/PVC pipes. Repairs to small sections of cast iron piping can range from $200 to $1000.

PEX or PVC is recommended instead of cast iron pipes because they are cheaper, lighter, and last longer than cast iron pipes.

How Long Do Cast Iron Pipes Last in Florida?

Cast Iron pipes in Florida last anywhere from 80-100 years.

How to Make My Cast Iron Sewer Pipe Last Longer?

Ensure each sewer line is installed with proper pitch. Every piece of pipe must have a proper slope.

Each piece of cast iron needs to be supported at each end to avoid settlement. Settlement ruins the pitch of the pipe and may cause the pipe to snap or break.

Pipe joints must be sealed and kept tight, so water won’t leak. This is done by using approved gaskets or caulking the joints using molten lead or oakum.

Improper joints too can lead to root infiltration, or the pipes separating.

Use the cast iron sewer pipe correctly as misuse can ruin the life expectancy. That can take the form of grease being introduced into the drain system, or highly acidic or alkaline wastewater.

When backfilling over a sewer pipe installation, clean backfill material must be used. Each piece of pipe should have clean soil or crushed stone placed underneath it.

Can You Repair a Cast Iron Drain Pipe Yourself?

It depends. You can repair a tiny problematic section with a crack or leak yourself. However, if the leaks or fissures are all over the place, then now would be a good time to call in the experts to handle the repair of the pipes.

If you’re going to tackle the job yourself, you can use cast iron repair paste of plumber’s epoxy. This will fix any holes or leaks.

Should You Repair or Replace Cast Iron Drain Pipes?

Repairing a cast iron pipe is only a temporary solution. It will only worsen as the pipes become of age.

Cast pipes are designed to last only 50 years so, with time, they will crumble, leak or crack on each side of the repair. Such is the nature of cast iron.

If you need to budget for the replacement job or quickly stop a leak, by all means, have a spot repair done while keeping the age of the pipe in mind. But certainly, aim for replacing your pipes as soon as you can.

How do the Professionals Repair a Cast Iron Drain Pipe?

First, experts will send a tiny camera through all your pipes. This camera will measure and record the condition of your pipes.

This action uncovers the problems and provides them with information on what method or repair is best.

Here are two band-aid repair jobs they can do to fix the issue:

  • Spot Repairs

Spot repairs are patch job that fixes the affected area temporarily. They are not a permanent solution.

  • Point Repairs

These are like cured-in-place pipes. What the experts do here is to install a CIPP liner in the small section of the pipe that requires repair.

Author: Howard S. Baldwin

My name is Howard S. Baldwin. I am a work-at-home dad to three lovely girls, Jane + Hannah + Beauty. I have been blogging for the last 3 years. I worked for other Home and Lifetsyle blogs, did hundreds of product reviews and buyers’ guides. Prior to that, I was a staff accountant at a big accounting firm. Needless to say, researching and numbers are my passion. My goal is to be an informative source for any topic that relates to DIY life and homemaking.

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