Why window wells flood
A window well is an open pit, usually lined with a corrugated metal or plastic liner, that lets light and air reach a basement window below ground level. Rain that falls directly into a small well is usually not a problem if the bottom drains. Trouble starts when much more water arrives than the well can drain:
- a downspout discharging next to the well;
- an overflowing gutter above the well, often at a corner or valley;
- ground that slopes toward the house, sending yard runoff into the well;
- a well bottom that does not drain, because of compacted soil, clay or a clogged drain;
- snow drifted into the well that melts in spring.
Once the water rises above the window sill, it can leak through the window frame, or the glass can break under pressure. Water in the well also soaks the foundation wall around the window.
Step 1: Look up
Before changing anything at the well, look at the roof edge above it. Is there a downspout nearby? Does the gutter overflow there in heavy rain? Inside corners and roof valleys concentrate water and often overflow directly above window wells. Fixes include:
- moving or extending the downspout so it discharges well away from the well;
- adding a downspout or upgrading to 3x4-inch downspouts to stop overflow;
- installing a splash guard at an inside corner;
- upgrading to 6-inch gutters where the roof sheds more than the gutter can carry.
See gutters overflowing in heavy rain, roof valleys and gutter overflow and downspout size and placement.
Step 2: Move the discharge
Downspouts should never empty into or next to a window well. Carry the water at least several feet away onto ground that slopes away from the house, or into a buried line that discharges farther away. Make sure extensions are in place year-round; a flip-up extension left up in winter can send snowmelt straight into the well in spring. See downspouts and your foundation and underground downspout drainage.
Step 3: Fix the grading
The ground around the well should slope away from the house. Settled soil next to the foundation often creates a low spot that funnels water toward the well. Adding soil to restore slope, keeping mulch and landscaping from creating dams and setting the top of the well liner a few inches above the surrounding grade all help. See gutters and landscaping.
Step 4: Make sure the well drains
The bottom of the well should drain. Common approaches are a layer of gravel over permeable soil, or a drain at the bottom connected to the foundation drainage system. If the well holds water for long after rain, the drain may be clogged or missing. A contractor who specializes in basements or drainage can check it.
Step 5: Consider a cover
Clear covers keep rain, snow and debris out while letting light in. They are useful where wells sit under a roof edge or where snow drifts. For egress windows, which are meant as an emergency exit from a basement bedroom, covers must open easily from inside, so choose covers designed for egress wells and check local code.
Order matters
Many homeowners start with covers or drains, but the cheapest and most effective fix is often at the roof edge: a downspout moved a few feet or an overflowing corner fixed. Start at the top, then work down to the grading and the well itself. See wet basement? check gutters first.
Signs the well is the problem
Water stains or efflorescence (a white, powdery residue) below a basement window, damp drywall around the window frame, rust on a metal well liner or debris and standing water at the bottom of the well all point to a window well that is collecting more water than it can drain. If the stains appear only after heavy rain, look for a nearby downspout or overflow. If they appear in spring, look for snowmelt and frozen drains. If they appear after every rain, check the grading and the well drain. Matching the timing of the leak to the weather is often the quickest way to find the cause.
Liners, gravel and debris
Leaves, mulch and trash collect at the bottom of window wells and slow drainage. Clearing them out once or twice a year keeps the gravel or drain working. A liner that has separated from the foundation lets water run down the wall behind it; it should be fastened tightly and sealed where it meets the wall. These are simple checks to do while looking at the downspouts.
Snowmelt and ice
In cold climates, snow drifts into window wells and melts in spring, often while the ground is still frozen and cannot absorb water. Ice in a clogged well drain stops it from working. Covers and downspout extensions that stay in place through winter help most here. See ice dams and gutters.
New basement windows
If you are adding egress windows to finish a basement, plan downspout locations at the same time. A new window well dug next to an existing downspout is a common mistake that floods the new bedroom in the first big storm.
What to tell the gutter installer
- Point out every window well and any history of water in them.
- Ask where each downspout will discharge relative to the wells.
- Ask whether gutters above the wells overflow and how that will be fixed.
- Ask for extensions or buried lines that stay in place year-round.
See how to compare gutter quotes.
Related guides
For rural homes with wells and septic systems, see gutters on rural homes. For walks and steps that ice up, see downspouts and icy walkways. For homes that sit empty, see gutters for seasonal and vacation homes.