If your home in Evanston or Palatine was built before about 1975, the drain pipes inside your walls and under your basement floor are almost certainly cast iron. Cast iron was excellent pipe — durable, quiet, and heavy — but it does not last forever. Most of it is now 60 to 100 years old, and the failures are becoming routine.
This guide explains how to tell whether your cast iron drain stack is nearing the end, what replacement involves, and what it costs. It is a different job than sewer line replacement outside the house, and the two get confused constantly.
Inside vs. Outside: Know Which Pipe You’re Talking About
Homeowners often call about “replacing the sewer” when they mean two different things:
- The sewer lateral — the buried pipe from your house to the municipal main in the street. Usually clay or cast iron. Repaired by excavation or trenchless lining.
- The drain, waste and vent (DWV) system — the cast iron stack running vertically through your walls, the horizontal branches serving each fixture, and the building drain under the basement slab. This is the subject of this article.
You can have a perfectly good sewer lateral and a badly deteriorated stack, or the reverse. A camera inspection tells you which. See our drain and sewer inspection services if you are not sure what you have.
How Cast Iron Drain Pipe Actually Fails
Cast iron does not fail evenly. It corrodes from the inside out, and the pattern is predictable:
Channeling in horizontal runs
Waste flowing along the bottom of a horizontal pipe corrodes that surface faster than the rest. Over decades the bottom of the pipe thins and eventually opens into a channel, while the top of the pipe still looks fine. Under a basement slab, this leaks into the soil for years before anyone notices — often showing up as a sewer smell, settling floor tile, or a damp spot.
Tuberculation and restriction
Corrosion builds rough nodules inside the pipe, catching debris and shrinking the effective diameter. A 4-inch stack can be functionally 2 inches. This is why an old house has drains that back up despite repeated snaking — the snake clears the blockage but the restriction remains.
Cracked hubs and failed joints
Original cast iron joints were sealed with oakum and molten lead. As the building settles and the metal corrodes, those joints crack, leaking at the connection points inside walls.
Vertical stacks fail last
Because waste passes through quickly and does not sit, vertical stacks usually outlast horizontal runs. This matters for budgeting — you may only need to replace the under-slab building drain and basement branches, not the entire system.
Warning Signs You Should Not Ignore
- Repeated backups in the lowest fixtures despite regular snaking
- Persistent sewer odor in the basement with no visible source
- Slow drains throughout the house, not just one fixture
- Rust-colored stains or flaking on visible cast iron in the basement
- Cracked or settling basement floor tile or concrete along a pipe route
- Gurgling from a floor drain when an upstairs fixture runs
- Water stains on a ceiling below a bathroom with no supply leak found
- Unexplained increase in basement humidity or a musty smell
Any two of these together warrant a camera inspection before you finish another basement or remodel a bathroom.
Diagnosis: What a Proper Inspection Looks Like
We do not recommend replacement based on age alone. The evaluation includes:
- Camera inspection of the building drain and accessible branches, documenting wall thickness loss, channeling, offsets, and standing water
- Visual survey of exposed cast iron in the basement — tapping for soundness, checking joints and hangers
- Flow testing to see how the system handles simultaneous fixture use
- A written scope identifying which sections need replacement now, which should be monitored, and which are fine
A good inspection frequently saves money by scoping the work down. “Replace everything” is rarely the honest answer.
Replacement Methods and Costs
Under-slab building drain replacement
The most common major job. The basement floor is saw-cut along the pipe route, the trench excavated, old cast iron removed, new PVC installed at proper slope, then backfilled and the slab patched.
Cost: $120–$250 per linear foot in the Chicago suburbs, typically $6,000–$18,000 for a whole-house building drain depending on length, depth, and how many branch connections and floor drains are involved.
Vertical stack replacement
Requires opening walls on each floor the stack passes through. The old stack is cut out in sections and replaced with PVC or, where noise matters, cast iron or heavy-wall PVC with sound insulation.
Cost: $3,500–$9,000 per stack, plus drywall and finish repair. Best done during a bathroom remodel when the walls are already open — the savings are substantial.
Branch line replacement
Individual fixture runs in a basement ceiling or crawl space, where access is easy.
Cost: $800–$3,000 per branch.
Epoxy lining (cured-in-place)
A liner is inserted and cured inside the existing pipe, forming a new pipe within the old one. It avoids demolition, which is genuinely valuable when the pipe runs under a finished basement or a structural element.
Cost: $80–$200 per linear foot.
Honest limitation: lining requires the host pipe to have enough structural integrity to hold the liner, so severely channeled or collapsed sections cannot be lined. It also slightly reduces diameter and complicates future branch tie-ins. It is a good tool for the right situation and oversold for the wrong one.
Cost Comparison
| Approach | Typical Cost | Disruption | Expected Life |
|---|---|---|---|
| Snaking / hydro-jetting only | $250–$700 | None | Months to a few years |
| Spot repair of one section | $1,200–$3,500 | Low | Depends on rest of system |
| Epoxy lining | $80–$200/ft | Low | 40–50 years |
| Under-slab replacement (PVC) | $120–$250/ft | High | 75+ years |
| Full stack + branch replacement | $10,000–$30,000 | High | 75+ years |
Ranges reflect 2026 Evanston and Palatine area pricing and vary with access, depth, and finish repair scope.
Timing: When to Do This Work
The best time to replace cast iron is when you are already opening things up:
- Before finishing a basement. Replacing an under-slab drain after you have finished the basement means demolishing new work. Do the camera inspection first — always.
- During a bathroom remodel. The stack and branches for that bathroom are already exposed.
- When buying an older home. Negotiate it into the transaction if the inspection finds deterioration.
- After the second backup. If you have snaked the same line twice in a year, you are renting a solution.
The worst time is after a failure floods a finished space, when you pay for the pipe and the restoration.
What Replacement Day Looks Like
For an under-slab job, expect a crew on site for three to seven days. Day one is protection, saw-cutting, and dust containment — good contractors use plastic barriers and negative air machines because concrete dust travels through an entire house. Days two through four are excavation, removal, and new PVC installation with inspection of slope. Then the municipal inspection, backfill, and slab patch. Water service is typically shut off for only short windows, but drains will be out of service during working hours, so plan accordingly.
Permits are required in Evanston, Palatine, and every surrounding municipality, with an inspection of the new drain before it is covered. Never let anyone backfill before the inspection passes.
Frequently Asked Questions
How long does cast iron drain pipe last?
Typically 50 to 100 years depending on soil conditions, water chemistry, and use. Under-slab horizontal runs fail earliest, often at 50–70 years.
Is PVC noisier than cast iron?
Yes, noticeably, in walls adjacent to living space. Options include heavy-wall PVC, wrapping the pipe with mass-loaded vinyl, or using modern hubless cast iron for stacks in sensitive locations. We discuss this before specifying material.
Will homeowners insurance cover it?
Generally no for the pipe replacement itself, which is considered maintenance. Resulting water damage may be covered depending on policy and whether the failure was sudden. Check with your carrier before assuming either way.
Can I just keep snaking it?
For a while. But once the pipe is channeled, a snake can accelerate the failure by punching through thin walls. If a camera shows channeling, snaking is buying time, not fixing anything.
Do you offer financing?
Yes. We offer Sunbit and PowerPay financing, which matters on a project of this size.
Find Out What You Actually Have
MMDS handles camera inspections, drain replacement, and the concrete and finish work that comes with it in Evanston, Palatine, and throughout the Chicago suburbs. We will show you the camera footage and give you a scoped, honest recommendation — including telling you when the answer is “not yet.”
Call (847) 221-6280 or schedule an inspection before your next backup becomes a flood.