Cast Iron Drain Under Slab Cost (2026): $5,519 to $8,491
Replacing 22 feet of cracked cast iron drain under a basement slab costs about $5,519 to $8,491. 22 feet of cracked cast iron under an unfinished basement floor cut out and replaced with PVC: saw-cut, trench, pipe, backfill and the slab patch, itemized with crew hours.
Describe it
Every line, by trade
The job in the Clamp app: described in plain words, then the estimate at $4,245.25 job cost, every line grouped by trade. Sample data. Illustration of the Clamp app.
The job at a glance
One build, fully itemized, with crew hours.
| Build | Job cost | Labor | Crew hours | Materials | Illustrative selling price |
|---|---|---|---|---|---|
| A. 22 ft cast iron to PVC | $4,245 | $3,183 | 28 to 42 h | $612 | $5,519 to $8,491 |
Dump fees and other costs ($450) are the same in every build and included in the job cost. Materials include allowances. Illustrative selling price is the job cost at a 30% to 100% markup; your price depends on your own overhead and profit. Labor hours are a planning range and include setup, daily cleanup and material runs; they are never a charge to the customer. Permit and inspection fees are not included; requirements vary by jurisdiction.
Which price is closer to yours?
- Lean, +30%: A handyman or owner-operator who does the work with a small crew and no office. Usually the lowest quote. The owner handles scheduling, questions and callbacks around the work itself.
- Standard, +50%: A remodeling company with a crew, an office, insurance and someone to answer the phone. Close to the average remodeler's overhead in the National Association of Home Builders cost-of-doing-business survey.
- Full-Service, +100%: A design-build firm with designers, a salesperson and a project manager who runs the job. The extra pays for planning, coordination and one point of contact from design to final inspection.
Higher markup means more business behind the job, not by itself better work, and a lower markup is not by itself a better deal. For contractors: how each markup splits into overhead and profit is in the overhead categories guide.
The build in detail
A. 22 ft cast iron to PVC: $4,245
The bad section is confirmed on camera; 22 feet of slab is saw-cut and trenched; the cracked cast iron comes out and new PVC is tied into the sound pipe at both ends, bedded and backfilled; the slab strip is repoured and the debris hauled off. Labor is $3,183 of the $4,245 job cost, or 75.0%. It is about 28 to 42 hours of work, including setup, daily cleanup and material runs.
Labor cost by trade
Labor only. Materials, allowances and dump fees are in the line items below. Hours are person-hours at typical production from Clamp’s labor hours catalog, as a range: a planning figure, not a schedule and not a charge to the customer.
| Trade | Hours | Labor cost | Lean×1.30 | Standard×1.50 | Full-Service×2.00 |
|---|---|---|---|---|---|
| Plumbing | 24 to 37 h | $3,183 | $4,138 | $4,775 | $6,366 |
| Setup, cleanup and material runs | 2 to 7 h | in the prices | |||
| All labor | 28 to 42 h | $3,183 | $4,138 | $4,775 | $6,366 |
Every line item
Labor $3,183 + materials and allowances $612 + dump fees and other $450 = $4,245 direct job cost. Hours are person-hours at typical production, on labor rows only, and the direct-cost row adds about 15% for setup, daily cleanup and material runs; an allowance or material row names the labor line that installs it, and a subcontract row has none, because the sub’s price includes their own time. Some labor quantities include a difficulty factor, so they can exceed the measured area; each row’s derivation is in the downloadable data.
| Item | Qty | Unit | Hours | Labor | Material | Line cost |
|---|---|---|---|---|---|---|
| Demo & Prep | ||||||
| Debris Haul-Off (per Load) | 2 | ea | $0 | $0 | $450 | |
| Demo & Prep subtotal | $450 | |||||
| Demo & Prep subtotal | $450 | |||||
| Plumbing | ||||||
| Camera Inspection Labor | 1 | ea | 1 to 2 h | $325 | $0 | $325 |
| No-Hub Drain Coupling (per tie-in) | 2 | ea | $0 | $76 | $76 | |
| Pipe Bedding Stone (per lf of trench)Labor on: Sewer Lateral Pipe Lay Labor, Open Trench (per lf) | 22 | lf | $0 | $99 | $99 | |
| DWV MaterialsLabor on: Sewer Lateral Pipe Lay Labor, Open Trench (per lf) | 33 | lf | $0 | $206 | $206 | |
| Sewer Lateral Pipe Lay Labor, Open Trench (per lf) | 22 | lf | 2 to 6 h | $308 | $0 | $308 |
| Slab Saw-Cut and Trench (per lf) | 22 | lf | 10 to 21 h | $1,056 | $0 | $1,056 |
| Slab Trench Patch Labor | 22 | lf | 2 to 6 h | $374 | $0 | $374 |
| Slab Trench Patch Materials (per lf)Labor on: Slab Trench Patch Labor | 22 | lf | $0 | $231 | $231 | |
| Tie In to the Existing Cast Iron or Clay Drain (per tie-in) | 2 | ea | 3 to 7 h | $1,120 | $0 | $1,120 |
| Plumbing subtotal | 24 to 37 h | $3,795 | ||||
| Plumbing subtotal | 24 to 37 h | $3,795 | ||||
| DIRECT JOB COST | 28 to 42 h | $4,245 | ||||
| DIRECT JOB COST | 28 to 42 h | $4,245 | ||||
Methodology & reproducibility
One reviewed snapshot for this build. The build is frozen from its own estimate run and priced by the published pricer.
Direct cost equals the sum of each row’s rounded quantity × (labor + material + other). Amounts are shown in whole dollars; every column adds to its total.
Scope selection, prose accuracy, arithmetic and provenance mapping reviewed; not independent market-rate verification.
- cast-iron-drain-under-slab-22/v2: JSON, CSV, field dictionary
Questions
Why is most of this labor?
The pipe itself is cheap. Cutting, digging, hauling and patching 22 feet of concrete floor is the job, which is why the slab and trench lines outweigh the PVC.
What can push this job higher?
More bad pipe than the camera showed, a deeper drain, a finished floor that has to come up and go back, or a break that reaches the exterior lateral. Each is its own line.
Is the markup on top of this?
Yes. Direct job cost is what the repair costs a contractor to perform. The markup table shows what it sells for at illustrative markups of 30% to 100%.
Sources & provenance
- 22 ft cast iron to PVC reviewed snapshot Clamp Research