Drain Line Replacement — Cast Iron to PVC

What it is

Drain line replacement covers removing corroded, cracked, or collapsing cast iron drain and waste lines — usually in a crawlspace — and replacing them with modern schedule-40 PVC. We re-slope the run properly so waste flows the way it should and the new lines don't clog.

See also in Plumber: General Plumbing & Leak Repair, Water Heater Installation & Replacement.

When you need it

• Recurring drain clogs, slow drains, or gurgling from multiple fixtures
• Sewer smell inside the home or coming from the crawlspace
• Visible rust, cracks, flaking, or holes on cast iron drain lines under the house

What's required

We need crawlspace or basement access to the drain run, and the home's water use paused while the drain is open. Most single-run replacements are same-day; whole-house cast-iron-to-PVC swaps take 2–4 days depending on how much line is in the house.

Ready to start? Request a free estimate and we'll come measure.

Our Process

1. 1Inspect the drain run and identify failing sections.
2. 2Bid the replacement — partial run or whole-house — in writing.
3. 3Cut out the old cast iron, install new PVC with proper slope, tie into vents and stack, and test.

Why Us

Our San Antonio crew has been doing drain replacements for years — I've handled a lot of these besides showers. We work clean in tight crawlspaces and re-slope the new run so you're not calling anyone back for clogs. Full labor and parts warranty.

Pricing Notes

Cast-iron-to-PVC drain replacement cost in San Antonio varies with run length, crawlspace access, and how much of the system is being swapped — we give a written quote after an on-site look.