Window Well Drainage: Common Problems & Fixes

Why window wells flood

A window well is the metal or plastic enclosure that holds back soil around a below-grade basement window, and it's supposed to have its own drainage so rainwater doesn't just pool against the glass. When it wasn't built with proper drainage — or when a drain line clogs with silt over the years — the well fills up like a bucket every time it rains. Once water rises above the bottom of the window frame, it's a matter of time before it finds a way past the seal and into your basement.

Common causes and how to fix each one

• No gravel base or drain line. Many older or poorly built window wells were backfilled with soil instead of gravel, with no drain at all. Fix: excavate the well, add a perforated drain pipe at the bottom connected to your foundation drain system or a dry well, and backfill with clean gravel so water percolates down instead of pooling.
• Clogged drain line. If a drain exists but water still pools, the line may be silted up or crushed. Fix: have it snaked or excavated and cleared, and add a filter fabric over the gravel to slow future clogging.
• No well cover. An open window well collects rain, leaves, and debris directly. Fix: install a clear polycarbonate or metal-mesh cover — this alone eliminates most of the water a well ever has to handle, and keeps out debris that clogs drainage over time.
• Grading problems above the well. If the ground around the well slopes toward it instead of away, surface runoff pours straight in regardless of the well's own drainage. Fix: regrade the soil around the well to slope away from the foundation.
• Well too small or too shallow. Building code generally requires the well to extend several inches below the window sill with clearance in front of the window; an undersized well can overflow in heavy rain even with good drainage. Fix: this usually requires enlarging or rebuilding the well itself.

Pro tip from our network contractors

If the window is a legally required egress window (a bedroom's emergency exit), don't cover it with anything that can't be opened from inside in an emergency — a fixed grate or a cover that locks from outside only can turn a safety feature into a hazard. See our egress window guide before choosing a cover.

When it's more than just the well

If water is getting into your basement even after fixing the well itself, the problem may be broader foundation drainage — clogged gutters directing water toward the foundation, poor overall grading, or a failing foundation waterproofing membrane. A recurring wet basement is worth a broader look, not just a window-well fix in isolation.