Signs you need a french drain
French drains fix a specific problem: water that collects and lingers where it shouldn't. If you're seeing these signs, drainage is likely the culprit.
The common signs
- Standing water in the yard that lingers for hours or days after rain.
- A soggy, spongy lawn or persistent mud in the same low spots.
- Water in the basement or crawl space after storms — seeping at the wall-floor joint or through the slab.
- Efflorescence (white chalky mineral staining) or damp streaks on foundation walls.
- Water pooling against the foundation or a driveway/patio that sheds water back toward the house.
- Mulch, soil, or gravel washing out along a slope after every rain.
- A hillside or retaining wall that stays saturated and weeps.
What a french drain won't fix
A french drain moves liquid water. It won't solve a plumbing leak, high indoor humidity with no water source, or a roof/gutter problem dumping water at the foundation — fix the gutters and downspout extensions first, since that's cheaper and sometimes all you need. A good installer will check those before selling you a trench.