Whether you’re dealing with a flooded window well right now or trying to prevent one, this guide explains why it happens, what damage it can do, and which fixes work in GTA homes, including when a cover is enough and when the drain itself needs repair.
Window wells are the metal or plastic liners set into the ground around basement windows that sit below grade. They hold soil back from the glass and let light in, and for a bedroom egress window they provide a way out in an emergency. But because a window well is an open pit right next to your foundation, it also collects water. Heavy rain, poor grading, overflowing eavestroughs and a drain that is clogged, or was never installed, can all leave water pooling against the window.
Why Do Window Wells Fill With Water?
Wondering why your window well keeps filling up after rain? It’s a common problem in the GTA, especially during summer storms and spring thaws. These are the causes we see most often:
- Heavy rain and snowmelt. Thunderstorms and thaws send a lot of water toward your foundation in a short time, and rain also falls straight into an uncovered well.
- No drain, or a clogged one. Many window wells have no drain at all, or a drain buried under silt, leaves or settled gravel. With nowhere to go, the water rises toward the sill.
- Grading that slopes toward the house. Soil next to a foundation settles over time, especially in backfilled areas. When the ground slopes toward the house instead of away from it, runoff flows into the well.
- Downspouts and eavestroughs. A downspout that discharges beside the foundation, or an eavestrough overflowing above the window, can fill a well on its own.
- A well that sits too low or is damaged. If the top of the liner is level with or below the surrounding soil, surface water runs straight in. Rusted, bent or loose liners also let soil and water in at the joints and where the liner meets the wall.
- Frozen ground. In winter and early spring, frozen soil and ice can block drainage, so a mid-winter rain or a thaw can fill a well that drains fine in summer.
- Weeping tile problems. If the well drain connects to your weeping tile and that system is clogged or collapsed, the well can’t drain either. Learn more about whether weeping tile can get clogged.
These problems usually build slowly, which is why a window well can stay dry for years and then flood in a single storm.
If you’ve searched “Why is water leaking through my basement window?” or “How do I stop my window well from flooding?”, you’re in the right place.
Problems Caused by Flooded Window Wells
Standing water in a window well is more than a nuisance. Here’s what it can lead to:
- Water in the basement. Water finds gaps around the window frame and cracks in the wall below it, then damages drywall, flooring, insulation and anything stored nearby.
- Pressure on the window. Water pressing against the glass and frame can push past worn seals and, in severe cases, crack or break the glass.
- Frame damage and staining. Repeated soaking rots wooden frames, and evaporating water leaves mineral stains on the glass that are hard to remove.
- Mould and musty odours. Damp walls and trim around the window create the conditions mould needs. If you already notice a smell, see our guide on how to get rid of a musty smell in your basement.
- Foundation stress. Water held against the wall adds hydrostatic pressure, which can open new cracks or widen existing ones around the window opening. Leaking cracks need a proper basement crack repair, not just a surface patch.
Long-term risks of repeated window well flooding
- Rotting wooden window frames
- Rusted metal window well liners
- Cracked or deteriorated foundation walls below the window
- Higher humidity throughout the basement
Even small amounts of repeated moisture can shorten the life of your basement finishes. If water is already getting in, see how our basement waterproofing services can solve the problem for good.
Window Well Filling with Water? Here’s What to Do
If your window well is full of water right now
- Get the water out. Bail it with a bucket or a wet/dry shop vacuum. Stay clear of outlets and extension cords, and never stand in water near anything electrical.
- Stop more water coming in. Point nearby downspouts away from the house and, if more rain is coming, cover the well with a tarp sloped away from the wall.
- Clear the bottom. Remove leaves and debris, and uncover the drain grate if there is one. Pour in a bucket of water and watch whether it drains.
- Check inside. Look for water at the window and on the wall below it. Dry the area and run a dehumidifier or fan.
- Plan a permanent fix. If the well floods again, use the three fixes below, or call a waterproofing contractor.
Once the emergency is over, these three fixes make the biggest difference.
1. Install a Window Well Cover
A well-fitted window well cover is one of the simplest ways to keep rain, snow and debris out of the well. It works like a lid: water and snow run off the top instead of collecting at the bottom, and leaves and litter stay out, so the drain stays clear.
What a good cover does:
- Keeps rain and snowmelt from falling directly into the well
- Keeps out leaves, branches and litter that clog the drain
- Reduces the risk of children, pets and wildlife falling in
Common types of covers:
- Clear polycarbonate or acrylic covers (domed or lean-to). These let daylight into the basement while shedding water. Polycarbonate is more impact-resistant than acrylic, which matters where snow, ice or foot traffic is likely.
- Metal grates. Steel or aluminum grates are strong and good for fall protection, but on their own they don’t keep water or snow out. Some homeowners pair a grate with a clear cover.
- Custom-fit covers. Odd-shaped or oversized wells often need a cover made to measure. A cover that leaves gaps lets water in.
How to choose one:
- Fit. Measure the well’s width, how far it projects from the wall, and its shape. The cover should seal against the liner and the wall.
- Slope. Choose a domed or sloped cover that sends water away from the house, not toward the wall.
- Snow load. GTA winters bring heavy, wet snow. Pick a cover rated to carry it, and brush snow off after big storms.
- Egress windows. If the window is a bedroom egress window, the cover must open easily from the inside without tools, keys or special knowledge, so the window still works as an emergency exit under the Ontario Building Code. If you’re not sure, check with your municipality’s building department before installing one.
- Secure attachment. The cover should be fastened so wind can’t lift it.
What a cover can’t do: it stops water from above, but it won’t stop groundwater or runoff that seeps into the well through the soil, and it won’t fix a blocked drain. If water rises up through the gravel at the bottom of the well, the drain or your weeping tile is the real problem. Pair a cover with a working drain for full protection.
2. Install a Proper Window Well Drain
Every window well needs a way to drain. The most reliable setup is a vertical drain pipe that runs from the bottom of the well down to the weeping tile at the footing of your foundation. Water that gets into the well then flows into the same drainage system that protects the rest of your foundation, instead of sitting against the window.
How a window well drain is typically installed:
- Excavate beside the well down to the footing. In tight spaces, next to decks or close to landscaping, this is often done by hand to limit damage.
- Inspect the weeping tile. Repair or replace damaged or clogged sections so the new drain has somewhere to go. (See our weeping tile installation service.)
- Install the vertical drain pipe from the floor of the well down to the weeping tile, with a grate or cap on top to keep debris out.
- Backfill with clear gravel around the pipe, and fill the bottom of the well with clear gravel so water can reach the drain. Keep the gravel several inches below the window sill (about 15 cm, or 6 in, is a common target).
- Secure the liner and fix the grading. Fasten the liner to the foundation, make sure its top sits a few inches above the surrounding soil, and slope the soil away from the well and the house.
- Test it. Run a hose into the well and confirm the water drains away steadily.
When the weeping tile isn’t an option: in some older homes the original weeping tile is clay tile that has cracked, filled with silt or been blocked by roots. Connecting a new well drain to it won’t help. Options include replacing the weeping tile, draining to a French drain or drywell away from the house, or adding interior waterproofing with a sump pump. Which one is right depends on your foundation, lot and existing drainage.
DIY or professional? Clearing debris, replacing silted gravel and testing the drain are reasonable DIY jobs. Digging down to the footing next to your foundation is not. It’s deep, the trench can collapse, and you need utility locates first (in Ontario, request them free through Ontario One Call before you dig).
For example, on a hand-excavated exterior waterproofing project in Oakville, our scope included installing a vertical drain in the window well and fastening the well to the foundation wall, along with crack repair, a rubberized membrane and weeping tile repair.
3. Perform Regular Window Well Maintenance
A little maintenance goes a long way. Open wells collect leaves, branches and dirt, and even covered wells silt up over time. Once debris blocks the drain, the next storm fills the well. Check your window wells every spring and fall, and after any major storm:
- Clear debris. Remove leaves, litter and anything that has blown in.
- Test the drain. Pour in a bucket of water. It should drain away steadily within a few minutes. If it pools, the drain or the gravel is clogged.
- Refresh the gravel. Gravel that’s packed with silt drains slowly. Replace the top layer, or all of it if needed.
- Inspect the cover. Look for cracks, gaps and loose fasteners, and clear heavy snow off in winter.
- Check eavestroughs and downspouts. Clean eavestroughs above the window and extend downspouts so they release water well away from the foundation (a common guideline is at least 1.8 m, or 6 ft), without sending it onto a neighbour’s property.
- Check the grading. Top up settled soil so the ground slopes away from the house.
- Look inside. Watch for staining, white powdery deposits (efflorescence), peeling paint or damp drywall around the window.
Ask yourself: “When was the last time I checked my window wells?” If it’s been a while, now is the time to inspect them, before the next rainstorm or thaw.
When to Call a Waterproofing Contractor
Call a professional if:
- The well floods even though it has a cover
- Water rises up through the gravel instead of draining down
- The well still drains slowly after you’ve cleared it
- Water is getting in around the window or through the wall below it
- You see cracks in the foundation wall below the window
- The liner is rusted, bent or pulling away from the wall
- You want a larger egress window or a new window well (see our page on egress window wall cutouts and our basement window enlargement project in Oakville)
Repeated window well flooding is often a sign of a deeper drainage or foundation issue. A local waterproofing contractor can find the root cause and recommend a long-term fix rather than a temporary patch.
GJ MacRae Foundation Repair has been waterproofing homes in Toronto and the GTA since 1975, and our office is in Oakville (see our basement waterproofing services in Oakville). We hand-excavate window wells, repair or replace weeping tile, install window well drains and liners, and handle complete exterior and interior basement waterproofing. Learn more about our window well repair and installation.
Dealing with a window well that keeps flooding? Call us at (905) 824-2557 or request a free quote.
