2026 cost reference
Interior and exterior systems are not interchangeable
Interior perimeter drains manage water after it reaches the foundation and usually involve cutting the basement slab. Current published interior-system pricing commonly assumes connection to a sump, while exterior footing drains require excavation and may drain by gravity.
A cheaper waterproofing quote may cover a different scope
One proposal may include paint or crack sealing while another includes a full perimeter drain, sump basin, pump and discharge line. RepairGauge therefore does not automatically stack a second sump-pump allowance on top of the interior per-foot system reference.
Finished basements need a second budget
Drywall, flooring, trim, mold remediation and finish restoration are intentionally excluded from the drainage calculator unless they are measured separately. This avoids applying a generic finish allowance to every basement.
The calculator uses the same reviewed source ranges shown on this page.
These figures may be quoted with attribution and a link. Source-check date: August 29, 2026.