Basement Flooding and Yard Pooling: French Drains, Sump Pumps, and Groundwater

DC homeowner: yard pools (rarely dries), sump pump runs every 2 min. Contractors suggest French drains. Basement is below grade; sump is below basement. Photos show swale near tree.

Diagnose First: Surface Water vs. Groundwater

• French drains intercept surface/subsurface flow above water table.
• If water table is high (pool never dries, sump runs constantly), French drains won't work—they fill from below.

System Options

1. Perimeter footing drain (perforated pipe at foundation base) + FIN drain (dimple membrane on wall) → sump pit.
2. Interior drain tile (under slab) → sump (if exterior excavation impossible).
3. Sump discharge: Pipe to storm sewer (permit + licensed plumber) or surface daylight far downhill.
4. Yard pool: If groundwater, fill with imported soil (permit >5 cy). Or pump from pool to daylight/swale.
5. Swale utilization: Natural swale near tree may be improved as surface drain path.

Critical

Get a site drainage analysis (engineer or qualified designer) before spending. Whole-property solution > piecemeal fixes.

Expert: Mark Harshman | www.prestoexperts.com/expert/markland