Cost of Under Slab Plumbing Repairs

The cost of under slab plumbing repairs primarily consists of the cost of tunneling and the cost of trenching.

We know you want some idea of the cost of under slab plumbing repairs. We are not going to give you the generic “it depends” answer. What we will do is give you several estimates based on a “common” or “most frequent situation” where older drain and sewer lines are replaced under slab.



Some trenching will be necessary to replace drain lines from the building perimeter to the city’s main sewer line.


Tunneling will be required for the under slab drain and sewer line replacement.

Cost Variables

Under slab plumbing repair costs can easily vary up to 50% or more because of rocky or difficult soils that have to be trenched and tunneled. Other factors that can increase the cost of an under slab leak repair job are trees, larger lots requiring more trenching, larger houses requiring more tunneling, concrete removal and repair, and drain lines under concrete patios and driveways.

Average Cost of Under Slab Plumbing Repairs

$4050 – Trenching – 90 feet at $45/foot (includes PVC pipes and materials)

$6250 – Tunneling – 25 feet at $250/foot (includes PVC pipes and materials)

$425 – Engineering + Permits
$10,725 – Total for “Average” Under Slab Plumbing Repair Job

$2,500 – $5,000   Total for smaller jobs

$15,000 – $20,000+   Total for larger jobs

Please call us with any questions about your plumbing issues or our plumbing services. We can give you a firm estimate after a complete inspection.

*Note – We strongly recommend plumbing inspections AFTER any foundation leveling or repair work has been completed. The process of lifting concrete slab foundations to their original elevation can and does damage sewer lines and drain lines.

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