How window wells leak
A window well is the open pit outside a basement window that sits below ground level. Its job is to hold back soil and let light and air in – and, for egress windows, to let people out in an emergency. Because it is a hole next to the foundation, it also collects water: rain falls straight in, roof water may splash in, and surface water from the yard can run in. If the water cannot drain away, it rises until it finds a way through the window frame, the seal around it or the wall below.
Common causes
- No drain or a clogged drain at the bottom of the well. Leaves, soil and debris can block drains or the gravel layer.
- Gutters overflowing or a downspout discharging next to the well.
- Grading that slopes toward the well, so yard water runs into it.
- Well liner not sealed to the foundation, letting soil and water wash in at the sides.
- Old windows with failed caulk, rotted frames or cracked glass block.
- Snow and ice packed into the well and melting all at once in spring.
Quick fixes
- Clean out leaves, soil and debris down to the gravel or drain.
- Pour a bucket of water into the well and watch whether it drains within a few minutes.
- Fix gutters and redirect downspouts away from the well.
- Add a clear window well cover to keep rain and snow out (egress wells need covers that can be opened from inside).
- Re-caulk the window frame and replace cracked panes or failed glass block.
- Build up the soil around the well so the ground slopes away from it.
What the building code says
The International Residential Code requires window wells to be designed for proper drainage by connecting to the building’s foundation drainage system or by an approved alternative method, with an exception for foundations on well-drained sand and gravel soils, as summarized in the City of St. Paul’s egress window handout. Many older homes predate that requirement and have wells with no drain at all.
Lasting repairs
- Install a drain in the well: a vertical pipe down to the footing drain or an interior drainage system, with clean gravel on top.
- Connect the well to an interior perimeter drain if you have one or are installing one – see basement waterproofing.
- Replace the window with a modern, well-sealed unit; for bedrooms, an egress window meeting current code.
- Replace a rusted or loose liner and seal it to the foundation.
- Improve grading: at least 6 inches of fall in the first 10 feet from the foundation (IRC R401.3).
When it’s more than the window well
If water also appears along the base of the walls or comes up through the floor, the window well is only part of the problem; the soil around the house is saturated. Read water in the basement after heavy rain to sort out the source, and see the snowmelt checklist if leaks appear mainly in spring.