Cast Iron Pipe Replacement Cost: South Florida Figures

Reported South Florida cast iron replacement runs $80 to $250 per linear foot, with whole-home replacement averaging near $10,000. The wide band is set by whether the pipe is under the yard or under the slab, since interior work carries floor demolition, containment and rebuild on top of the plumbing.

Cast iron replacement is the largest plumbing invoice most Broward homeowners will ever see, and the number depends far less on how much pipe there is than on where it runs.

The reported ranges

Scope	Reported figure	Note
Per linear foot, South Florida	$80–$250	Varies with depth and surface above
Whole-home replacement, average	~$10,000	Regional contractor reporting
10 ft under-slab section, quoted	$14,300	1964 Florida house under contract
Observed job range	$5,000–$40,000	Plumber, public forum

The $14,300 quote for ten feet is the figure that explains the whole page. Ten feet of four-inch pipe is a trivial material cost. That quote is concrete saw-cutting, dust containment, spoil removal, the plumbing itself, backfill and compaction, new concrete, and a floor put back — inside an occupied house.

Under the yard versus under the slab

Yard runs are the cheaper half of the problem. An excavator, a trench, new pipe to spec, backfill, and sod. The house stays livable throughout and the restoration is landscaping.

Under-slab runs change the job into a construction project. The floor is cut, the trench is dug by hand inside the room, spoil is carried out through the house, and everything is reversed afterward. Tile, wood, and terrazzo floors rarely survive it. Families frequently move out for part of the work.

This is also why “replace the cast iron” and “replace the sewer line” are different quotes. A house may have a sound yard lateral and a failed under-slab drainage system, or the reverse, and only camera footage separates them.

What moves the number

Linear feet of pipe being replaced, which is the only genuinely per-foot variable
Depth, with a step change past roughly ten feet where trench collapse protection is required
Surface above the pipe — sod, pavers, driveway, pool deck, or interior finished floor
Number of fixture connections that have to be reinstated
Whether the run leaves the property line into Broward County right-of-way, which adds a Road Cut and Restoration Permit covering signage and striping, plus as-builts signed and sealed by a Florida-registered Professional Land Surveyor
Whether lining is possible instead, which removes most of the excavation cost

The alternative that is not always available

Lining a cast iron line rather than replacing it removes the excavation, which is where the money is. It requires a host pipe that still holds its shape and grade — a bellied, offset or collapsed line cannot be lined, and a line that has lost its bottom may or may not be a candidate depending on how much wall remains.

One Florida homeowner reported 30 feet relined for $4,500 against a competing quote of $14,000 for the same job. That spread is the argument for getting the line scoped and then getting more than one bid, in that order.

What goes back in

Florida’s Building Code, Chapter 7, permits PVC DWV in SDR26, SDR35, SDR41, PS50 or PS100 for sanitary drainage, so SDR 35 PVC is an approved residential spec here. The code’s clause for filled or unstable ground — written for exactly the sand and fill Broward is built on — lists ABS, cast iron, copper or copper-alloy, PVC and PP as conforming materials.

For pipe bursting, the code requires HDPE, SDR 17, conforming to ASTM F714, and requires the finished section to be inspected internally by video camera survey and approved by the code official.

The insurance angle that catches Florida owners

The cost of leaving old cast iron in place does not always arrive as a backup. In Florida it frequently arrives at renewal. Carriers here scrutinise original plumbing in older homes, and a homeowner in a Florida thread described the bind precisely: a plumber advised “don’t fix what isn’t broken,” but “insurers in Florida will look for any reason to charge more.”

That makes the decision partly a policy question rather than purely a plumbing one, and it is worth asking a carrier what documentation — a camera report, a replacement invoice — changes their position before committing to either path.

“We quote yard and under-slab separately because they are separate decisions. Plenty of houses only need one of them done now.”

For a quote written against your own camera footage, request a free quote.

Frequently asked questions

Will cast iron pipes affect my Florida homeowners insurance?

They can. Florida carriers examine original plumbing in older homes closely, and the cost of leaving cast iron in place sometimes arrives as a surcharge or a non-renewal rather than as a backup. Ask your carrier whether documented replacement or lining changes their position before deciding.

How much does it cost to replace cast iron pipes under a Florida slab?

Under-slab work is the most expensive case because the price is concrete, containment and floor rebuild rather than pipe. One Florida homeowner was quoted $14,300 for ten feet under a 1964 house. Whole-home cast iron replacement in South Florida averages near $10,000.

Should cast iron drain pipes be replaced?

Not automatically. Surface rust and scale are the expected condition of fifty-year-old cast iron and are not a verdict. Replacement is indicated by a named defect: channelling across multiple sections, a belly, an offset, or a collapse. A single crack in sound pipe is repairable.

How long does a sewer line replacement take?

A trenchless lining on a residential lateral is usually one or two days. An open-trench yard replacement typically runs two to four days including restoration. Under-slab replacement inside a house takes longer and often means moving out for part of it.