Cast Iron Pipe Replacement Cost: Full Breakdown (2026)
💰 Cost Breakdown
| Item | Low | Average | High |
|---|---|---|---|
| Sectional Cast Iron Repair (5–10 ft) Cutting out a short corroded or cracked section and splicing in PVC or ABS with fernco couplings. Best when damage is localized to one joint or belly. Requires opening a wall or ceiling for access but doesn't involve full-line replacement. | $800 | $1,500 | $2,500 |
| Full Stack Replacement (3-story vertical drain) Removing the vertical cast iron stack from basement to roof vent and replacing with PVC. This is the main drain artery of the house — all branch drains connect to it. Requires opening walls on each floor. Typically 30–50 feet of pipe. | $3,000 | $5,500 | $8,000 |
| Underground Sewer Line Replacement (dig-and-replace) Excavating the yard or basement slab to remove buried cast iron sewer line and replace with PVC Schedule 40. Includes backfill, compaction, and surface restoration. Length typically 20–80 feet from foundation to city connection. | $4,000 | $7,500 | $15,000 |
| Trenchless Pipe Lining (CIPP) Inserting a resin-saturated felt liner into the existing cast iron pipe and curing it in place with heat or UV light. Creates a new pipe-within-a-pipe with 50+ year lifespan. No digging required. Works on pipes 2–12 inches in diameter that haven't fully collapsed. | $4,500 | $8,000 | $12,000 |
| Pipe Bursting (trenchless full replacement) Pulling a new HDPE pipe through the existing cast iron line while simultaneously fracturing the old pipe outward. Requires only two access pits. Results in a completely new pipe rather than a liner. Best when the old pipe is too deteriorated for lining. | $5,000 | $9,000 | $15,000 |
| Camera Inspection and Diagnosis Running a CCTV sewer camera through the cast iron line to identify the location, severity, and extent of deterioration. Required before choosing a repair method. Many plumbers credit the inspection fee toward repair work. | $150 | $300 | $500 |
Sectional Cast Iron Repair (5–10 ft)
Cutting out a short corroded or cracked section and splicing in PVC or ABS with fernco couplings. Best when damage is localized to one joint or belly. Requires opening a wall or ceiling for access but doesn't involve full-line replacement.
Full Stack Replacement (3-story vertical drain)
Removing the vertical cast iron stack from basement to roof vent and replacing with PVC. This is the main drain artery of the house — all branch drains connect to it. Requires opening walls on each floor. Typically 30–50 feet of pipe.
Underground Sewer Line Replacement (dig-and-replace)
Excavating the yard or basement slab to remove buried cast iron sewer line and replace with PVC Schedule 40. Includes backfill, compaction, and surface restoration. Length typically 20–80 feet from foundation to city connection.
Trenchless Pipe Lining (CIPP)
Inserting a resin-saturated felt liner into the existing cast iron pipe and curing it in place with heat or UV light. Creates a new pipe-within-a-pipe with 50+ year lifespan. No digging required. Works on pipes 2–12 inches in diameter that haven't fully collapsed.
Pipe Bursting (trenchless full replacement)
Pulling a new HDPE pipe through the existing cast iron line while simultaneously fracturing the old pipe outward. Requires only two access pits. Results in a completely new pipe rather than a liner. Best when the old pipe is too deteriorated for lining.
Camera Inspection and Diagnosis
Running a CCTV sewer camera through the cast iron line to identify the location, severity, and extent of deterioration. Required before choosing a repair method. Many plumbers credit the inspection fee toward repair work.
📊 Factors That Impact Cost
Pipe Location and Accessibility
High ImpactPipes in open basements or crawl spaces cost far less to replace than pipes buried under concrete slabs, inside finished walls, or beneath landscaping. Slab-on-grade homes with under-slab cast iron pay 50–100% more due to concrete cutting and restoration.
Total Linear Footage
High ImpactMost plumbers price cast iron replacement at $80–$250 per linear foot depending on method and location. A 10-foot section repair vs. an 80-foot full sewer replacement is the difference between $1,500 and $12,000.
Replacement Method
High ImpactTraditional dig-and-replace is cheapest per foot but has the highest restoration costs (concrete, landscaping, flooring). Trenchless methods cost more for the plumbing work but eliminate restoration expenses. Total project cost often favors trenchless for under-slab and landscaped routes.
Number of Connections and Fittings
Medium ImpactEach branch line connection, cleanout, or change of direction adds complexity. A straight run is simple; a stack with 6 branch connections on 3 floors requires more labor, fittings, and testing. Expect $200–$500 per additional connection point.
Permit and Inspection Requirements
Low ImpactMost jurisdictions require a plumbing permit for drain line replacement ($75–$300). Some cities require a city inspector to witness the final connection to the municipal sewer. Permit costs are small relative to the project but add 1–2 weeks to the timeline.
Surface Restoration
Medium ImpactAfter dig-and-replace, you'll need concrete patching ($500–$2,000 for slabs), landscaping restoration ($500–$3,000), or driveway repair ($1,000–$4,000). These costs are often excluded from the plumber's base quote. Trenchless methods largely eliminate this category.
💡 Money-Saving Tips
Get a camera inspection before committing to full replacement
A $150–$300 camera inspection reveals exactly which sections need replacement. Many homeowners replace 80 feet of pipe when only 15 feet are deteriorated. The camera tells you whether you need a full replacement or a targeted sectional repair.
Replace only the horizontal runs if the vertical stack is sound
Cast iron deteriorates fastest in horizontal runs where water sits and corrodes the bottom. Vertical stacks often last 20–30 years longer because water flows through quickly. If the camera shows a sound stack, replace only the horizontal sections.
Combine with other planned work that requires opening walls or floors
If you're already planning a kitchen remodel, bathroom renovation, or basement finishing, schedule the pipe replacement first. Shared demolition and restoration costs can cut 20–30% off the effective pipe replacement price.
Ask about pipe lining for under-slab sections
Trenchless CIPP lining costs more per foot than PVC replacement, but when the pipe is under a concrete slab, the total cost including slab cutting, removal, and restoration makes dig-and-replace far more expensive. Lining eliminates all concrete work.
Check homeowner's insurance and home warranty coverage
Some homeowner's insurance policies cover sudden pipe failures (collapse, backup causing water damage). Home warranties may cover a portion of repair. Also check if your municipality offers a sewer lateral protection program — some cities share the cost of sewer line replacement to the main.