How much does an interior basement French drain cost?
The recorded interior basement drain reference is $40–$85 per ft, typically with a sump. Drain length, the discharge route and included restoration change the scope. It manages water collected inside the foundation.
A shallow yard drain is a different project. Use this site's calculator for basement work and our sister site's guide for yard French drains. Compare concrete reinstatement and finished-room restoration separately.
Key facts as of Oct 30, 2026. Sources and recorded dates.
SIGNS
Which signs call for an interior drainage assessment?
Persistent water at the slab edge is a reason to examine collection and drainage. First distinguish groundwater entry from plumbing leaks and condensation; those observations determine whether a perimeter drain is the right scope.
Guidance: PNNL Building America: Pre-retrofit assessment of crawlspaces and basements.
CAUSES
Why can water collect at the basement floor edge?
An absent or ineffective drainage system can leave water without a removal path. The inspector should establish how water arrives, whether an existing drain works and where the proposed system will discharge.
Guidance: PNNL Building America: Pre-retrofit assessment of crawlspaces and basements.
FIXES
What should an interior French drain include?
Compare the measured trench length, collection pipe, sump connection, outlet and concrete reinstatement. Record access through finished rooms and ask which finishes will be removed or replaced.
Keep yard drainage and exterior footing-drain work separate from the interior system. Ask for a confirmed scope before combining prices from different methods.
Guidance: PNNL Building America: Foundation wall water/damp-proofing; PNNL Building America: Pre-retrofit assessment of crawlspaces and basements.
Which costs belong in this scope?
| Work | Planning range |
|---|---|
| Interior drain tile / sump system | $40–$85 / ft |
The HomeGuide interior reference typically includes a sump; adding a separate pump would risk double counting. Generic French drain and yard installation guidance belongs to our sister site.
Read the basement waterproofing cost guide for the worked example and price factors, or calculate an estimate for your measured scope.
For outdoor runoff and yard drains, visit French Drain Installation Cost.
Sources and dates
Public guidance checked Oct 30, 2026. Cost references retain the recorded Oct 24, 2026 retrieval date; this guide adds no new price observations.
- PNNL Building America: Pre-retrofit assessment of crawlspaces and basements
- PNNL Building America: Foundation wall water/damp-proofing
- HomeGuide: french drain cost — recorded Oct 24, 2026.
Read how the calculator works and the source inventory for calculation limits.