Selling a House With Failing Cast-Iron Drain Pipes
2 min read · Last updated 2026-08-03 · Reviewed by Camilo Palacio, Licensed Florida Real Estate Professional (License #3280644, REALTOR®)
Cast-iron drain pipe typically lasts 75 to 100 years before it corrodes from the inside out, and most homes with it were built before 1975, so a lot of it is near or past that window. A sale doesn't require replacing it, but a buyer's inspector will likely run a camera down the line and flag corrosion, which can turn into a repair fight. Cash Flow Deals is one option that locks a net price before inspection reopens the number.
| Factor | Traditional Route | Cash Flow Deals |
|---|---|---|
| Inspection risk | A buyer's camera inspection can surface corrosion late and reopen price talks | Net price locked before the pipe condition gets renegotiated |
| Repair cost exposure | Full cast-iron replacement typically runs $8,000 to $25,000 depending on scope | Repairs are scoped after the price is already set |
| Financing | Some lenders and insurers push back on a visibly failing drain line | Doesn't hinge on a buyer's lender approving the plumbing first |
How Long Cast-Iron Drain Pipe Actually Lasts
Cast-iron drain and sewer pipe generally lasts 75 to 100 years before interior corrosion causes it to fail, though many systems start showing problems after 60 to 70 years depending on water chemistry and how well the system was maintained. Homes built before 1975 are the most likely to still have original cast iron, and much of that pipe is already near or past its expected lifespan.
The Warning Signs of a Failing Cast-Iron Line
Corrosion inside a cast-iron pipe narrows the interior diameter over time, which shows up as slow drains, gurgling sounds, recurring backups, and sometimes a sewage smell near the lowest drains in the house. Tree roots can also crack aging cast iron at the joints, letting water and waste leak into the soil around the foundation. Left long enough, a failing line can cause real structural damage underneath the house.
What a Camera Inspection Will Find, and What It Costs
A camera, or video, inspection of the drain line is the only reliable way to see the actual condition of cast-iron pipe, since it hides mostly underground and under slab. The inspection itself typically costs somewhere between $150 and $350 and shows exactly where corrosion, cracks, or blockages exist along the run. A standard home inspection during a sale doesn't always include this step unless the buyer or their inspector requests it specifically.
What Replacement Actually Costs
Replacing a full cast-iron drain system typically runs $8,000 to $25,000 depending on the length of the run, whether it's accessible or requires cutting through a slab, and local labor rates. A single damaged section can sometimes be repaired for $500 to $2,000 instead of replacing the whole line, if the rest of the system is still sound.
Cash Flow Deals' Process for Homes With Aging Plumbing
1. Request a net-price review that accounts for the plumbing's age and condition, no camera inspection required first. 2. Get a locked net number in writing before a buyer's inspector runs a scope down the line. 3. Cash Flow Deals connects the property with a real mortgage-qualified buyer, using a novation-based, flat-fee process arranged through a licensed local broker partner. 4. Title transfers once, directly from seller to buyer, at a closing date agreed to upfront.
Common questions
How do I know if my house has cast-iron pipes?
Homes built before the mid-1970s commonly used cast iron for drain and sewer lines. A licensed plumber can confirm the material with a camera inspection, since most of the pipe is hidden underground or under a slab.
Does a home inspector check cast-iron pipes automatically?
Not always. A standard visual home inspection usually doesn't include a camera scope of the drain line unless the buyer or inspector specifically requests one, so hidden corrosion can go unnoticed until later.
How much does it cost to replace cast-iron drain pipe?
A full replacement typically runs $8,000 to $25,000 depending on the length and accessibility of the line. A single damaged section can sometimes be repaired for $500 to $2,000 instead.
Can I sell a house with failing cast-iron pipes without fixing them first?
Yes, there's no requirement to replace the pipe before selling. The issue usually comes up during a buyer's inspection and turns into a repair credit or price negotiation instead.