Cast Iron Drain Pipe Replacement Cost: Complete Guide for 2024-25
What You Really Need to Know About Cast Iron Sewer Pipe Replacement Costs 2025
Let’s be honest—nobody gets excited about replacing cast-iron sewer pipes. But if you’ve got an old house and shady plumbing, eventually it’s gonna come up. So instead of freaking out when the plumber says “$100 per foot,” let’s break it down in a real way, and make sense of what’s going on—budget-wise and emotionally.
Cast Iron Sewer Pipe Replacement Cost
Below, we compare the costs of trenchless vs. traditional pipe replacement in 2025:
Traditional Pipe Replacement Cost
- Excavation: $3,500 to $7,500 depending on the extent of digging required.
- Pipe Replacement: $100 to $300 per linear foot, with average total costs ranging from $10,000 to $30,000 depending on the length of the pipe and any additional restoration needed.
- Restoration: The cost of repairing landscaping, driveways, or flooring after excavation can add another $7,500 to $10,000.
Trenchless Pipe Replacement Cost
- Trenchless Pipe Lining: The cast iron pipe replacement cost using trenchless pipe lining typically ranges from $125 to $175 per linear foot. This means total costs can range from $8,500 to $15,000 for most homes, depending on the length and condition of the pipes.
- Pipe Bursting & Landscaping: For more extensive damage, pipe bursting needs to be performed, requiring two excavations, one at the house and one out in the street. These excavations typically will add about $7,500 to the bursting price. The price for bursting will be about $150 per foot plus excavation and landscaping repair.
As you can see, the cast iron drain pipe replacement cost using trenchless methods is generally much lower than traditional replacement when factoring in excavation and restoration costs. Additionally, the trenchless process is much faster and far less disruptive, making it a more convenient option for homeowners.
What About Slab-Below-Concrete Pipes?
Yikes. This is the worst. If your cast-iron drain pipes run under the slab, you’re likely looking at the top end of costs because of all that concrete demo and replacement.
A full slab dig-up and cast iron sewer pipe replacement cost can run between $10,000 and $30,000+, depending on damage length, concrete depth, and house structure. Trenchless helps, but if pipes are under the slab you may still need to cut—so yes, it still gets expensive.
Why Cast Iron Pipes Fail?
You’re not paranoid—it’s not just you. Cast iron eventually rusts from the inside out. Add acidic soil, shifting earth, and tree roots, and your once-tough plumbing becomes brittle and crack-prone over decades. Think 50–75 years of wear and tear, and you’ve got yourself a reason to call your plumber.
Should You Replace or Repair?
If you’ve got multiple leaks, root invasion, or collapsing sections, patch cast pipe repair isn’t gonna cut it. A full replacement—whether trenchless or traditional—often makes more sense and costs less in the long run than continuous band-aids and backups.
How to Plan Ahead Without Freaking Out
Here’s how to keep your sanity (and savings account):
- Get a camera inspection to see what’s cracking and where.
- Ask about trenchless options (CIPP or bursting).
- Get detailed quotes for traditional vs. trenchless vs. slab work.
- Factor in yard, driveway, slab restoration costs.
- Budget a cushion—just in case you hit rock, roots, or surprises.
Summary Table: What You’re Looking At
- Per foot: $100–$300
- Full replacement cost: $10,000–$30,000+
- Trenchless lining: $125–$175/ft, $8k–$15k total
- Pipe bursting: Around $150/ft + $7500 in excavation + landscape restoration
- Slab replacement: $10k–$30k+ depending on complexity
Final Thoughts: It’s a Big Job, But You’ve Got This
Replacing cast-iron sewer pipes isn’t fun—but once it’s done, it’s DONE. No more worrying about leaks, backups, or basement disasters. If you’ve got old pipes, now’s the time to investigate and budget.
We at Restore Pipe are an experienced and highly-rated drain cleaning company and sewer repair specialists serving various counties in Utah, Idaho and Wyoming. We offer cutting-edge techniques such as pipe lining and pipe bursting, providing homeowners peace of mind knowing their plumbing issues will be resolved quickly and efficiently—without the mess. Get in touch with us today by dialing 801-564-0089 or filling out a quick form and let us take care of all your cast iron, concrete, and clay pipe repair needs.
Frequently Asked Questions
Q: How much does it cost to replace a cast iron pipe?
Replacing a cast iron pipe usually costs between $3,000 and $10,000, depending on how long the pipe is and where it’s located. If it’s under concrete or behind walls, expect to pay more because of the extra labor. Trenchless methods might cost a bit more upfront but can save money on digging and repairs.
Q: How much does a sewer line cost per foot?
The average cost is anywhere from $100 to $250 per foot. It goes up fast as far as the length of the line is concerned. On the lower side will be the cost if the work is straightforward in your backyard. However, you raise the cost with digging under driveways or trenchless methods. Every job is just slightly different.
Q: How long do cast iron sewer pipes last?
Cast iron pipes can generally endure 50-75 years and sometimes more. However, they start to rust, break, or simply clog tremendously after a few decades. If your home has been around since the 60s or before, it might be time to get them checked before something disgusting backs up in your basement.
Q: Can you repair a cast iron pipe?
You sure can—sometimes. If it’s a small crack or just some surface rust, a plumber might be able to patch it or line it from the inside. But if it’s super corroded or leaking in a bunch of places, a full replacement might be the smarter (and cleaner) route. No one wants to keep patching the same leaky mess every year.
Q: What is the life expectancy of cast iron sewer pipes?
Most of them make it around 50–75 years, depending on how they were installed, soil conditions, and how much abuse they’ve taken. If your pipes are hitting retirement age, it’s better to catch issues early rather than wait for a nasty surprise.
Q: How much does it cost to replace the cast iron drain pipe under the slab?
Well, the honest answer is: it can get quite pricey. Basically, if you ask me, it’s a range between $10,000 and $30,000 less or more. It really depends upon how long it is, where it passes through, and how difficult it is to access it. Considered expensive if somebody has to dig under slabs or behind walls. In the end, if you have those old cast iron pipes deteriorating away, maybe you want to splurge on it, just so you may feel at ease.
Q: How to stop a leak in a cast iron pipe?
Short-term, there are a few DIY fixes—like pipe clamps, epoxy putty, or repair tape. But honestly? Those are just temporary band-aids. If it’s a leak from corrosion or cracking, it’s usually a sign that the pipe’s on its last legs. Call a plumber, get it looked at, and they’ll help figure out if it can be fixed or needs to be swapped out.