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Window well flooding: causes, fixes and cleanup

By ARO Restorations · Updated October 6, 2026

Short answer

A window well floods when water runs into it faster than it can drain. The usual causes are a clogged or missing well drain, soil sloping towards the house and downspouts discharging nearby. Clear the drain, fit a cover, fix the grading, and dry any water that got inside within a day or two.

In this guide

How a window well is meant to work

A basement window below ground level sits in a well: a curved liner of steel, plastic or masonry that holds back the soil. Rain and snowmelt that fall into the well soak down through a layer of gravel. In a properly built well, a vertical drain pipe under the gravel carries the water down to the weeping tile at the footing, and from there to a sump pit or storm connection.

Many wells have no drain at all. They rely on the gravel and the soil beneath to absorb the water, which works in sandy ground and fails in clay.

Why it fills up

The drain is clogged with leaves, soil, mulch and silt
There is no drain, and the soil below is clay
The weeping tile it drains to is blocked, or the sump pump is not keeping up
The ground slopes towards the house, sending surface water into the well
A downspout discharges beside it, or an eavestrough overflows above it
The liner has pulled away from the wall, letting soil and water in behind it
The well is too low. The rim should stand above the surrounding soil.
Snow piled against the house melts into it
Ground water rises from below in spring or after long rain

How water gets inside

Window wells are not built to hold water. Once the level rises above the sill:

Water comes through the gap between the frame and the foundation
It pours through the window’s own seals and weep holes
An old window can give way under the pressure, releasing the whole well into the basement at once

The result is a sudden flood of muddy water, often in a finished basement or bedroom.

If the well is filling now

Stay out of standing water in the basement until the power to the area is off.
Bail or pump the well if you can do it safely. A small utility pump works.
Clear debris from the top of the gravel.
Divert water away with a downspout extension or sandbags.
Move belongings away from the window inside and protect the floor.
Do not open the window.

If water has come in

Photograph the well, the window and the damage
Extract the water
Treat it as contaminated. Water that has run across the ground carries soil, fertiliser and animal waste.
Remove wet carpet, underpad and other porous materials it soaked
Cut out wet drywall and insulation below the window. Water runs down inside the wall.
Dry the structure with dehumidifiers and air movers
Have the cause fixed before finishing the wall again

Drying has to start within a day or two to avoid mold. See what to do when your basement floods.

Fixing the well

Clear it. Remove leaves and debris. Dig out silted gravel and replace it with clean stone to a level several centimetres below the sill.

Test the drain. Run a hose into the well. If the water does not drain away steadily, the drain is blocked or missing. A blocked drain can sometimes be flushed or snaked. Adding a drain means excavating to the footing, which is a job for a drainage or waterproofing contractor.

Fit a cover. A clear, sloped cover keeps out rain, snow, leaves and animals, and still lets light in. Make sure it can be opened from inside if the window is a means of escape.

Fix the grading. The ground should fall away from the house for the first couple of metres. Top up settled soil around the well, keeping it below the rim.

Extend downspouts well away from the foundation, and clean the eavestroughs.

Reattach or replace the liner if it has come away from the wall, and seal the joint.

Replace a failed window. Modern basement windows seal far better than old steel-framed units. Recaulk the frame to the foundation.

Check the sump pump. If the well drains to the weeping tile, the sump has to cope. A battery backup keeps it running in a power cut.

Egress windows

A basement bedroom needs a window large enough to escape through, and its well has to be big enough to climb out of. These large wells collect more water and need a proper drain. Any cover must be easy to open from inside without tools.

Insurance

Water entering through a window well from heavy rain or melting snow is generally treated as overland or surface water. Standard home policies have traditionally excluded it. Overland water coverage is available as an endorsement from many insurers in Ontario, depending on your address. If the water backed up through the drains instead, sewer backup coverage is the relevant one. Check which you have. See overland water coverage in Ontario.

Seasonal checks

Autumn: clear leaves from wells and eavestroughs
Winter: do not pile snow against basement windows
Spring: check that wells are draining during the thaw
After storms: look for standing water and debris

More: basement flood cleanup.

Questions people ask

Why does my window well fill with water?

Usually because its drain is clogged or missing, the ground slopes towards the house, or a downspout or overflowing eavestrough is sending water into it.

How do I stop my window well from flooding?

Clear the debris and gravel, make sure the drain works, fit a sloped cover, slope the ground away from the house and extend nearby downspouts.

Do window wells need a drain?

In most soils, yes. A drain to the weeping tile carries water away. Wells without one rely on the ground to absorb water, which fails in clay.

Is window well flooding covered by insurance?

It is generally treated as overland water, which needs an overland water endorsement. Standard policies have traditionally excluded it.

Do window well covers work?

A sloped cover keeps out rain, snow and leaves and greatly reduces the water entering the well. It does not fix a blocked drain or poor grading.