A window well holding water is not one problem. It is three, and they need different answers. Before you buy a cover or dig anything up, find out which one you have.
Water from above
Rain and snow landing directly in the well, or running off the roof into it.
How to tell: the well fills during rain and drains slowly afterwards. It is dry in a dry week.
Fix: a cover, plus checking where the downspout discharges. A downspout emptying within a couple of metres of the well is putting the entire roof through it. Extending the discharge is the cheapest fix on this page.
Water from the side
Surface water running across the yard toward the foundation and over the lip of the well.
How to tell: the ground around the well is level or slopes toward the house, and the lip of the well sits at or below grade. You will often see a silt line inside the well showing where it came in.
Fix: regrade so the ground falls away from the foundation, and raise the well so the lip finishes above grade. A cover does nothing here — the water is coming in over the edge, not through the top.
Water from below
Groundwater rising through the base of the well, which is what happens when the base is packed clay rather than free-draining stone.
How to tell: the well holds water for days after the rain stops, or fills in spring with no rain at all. This is the one people mistake for a leak.
Fix: excavate the base and rebuild it — six to eight inches of clear crushed stone, tied into weeping tile if you can reach it. This is the only one of the three that requires digging, and the only one a cover will never solve. The installation guide covers how to build the base properly.
Why clay backfill causes it
If the well was installed by backfilling with the excavated soil, the well is now sitting in a clay bowl. Clay's permeability is low enough that water arriving faster than it can soak away simply stands, and the lowest point it can stand in is your window well.
This is why we say the same thing on every city page: use clear crushed stone against the well, not the material you dug out. On the expansive clays of Regina, Saskatoon and Winnipeg it matters more than anywhere else, because that ground also moves seasonally and works the well out of square while it is at it.
What standing water actually damages
In order of how expensive it gets:
- The sill and frame. A wooden sill sitting in water rots, and the rot starts on the outside face where you cannot see it.
- The seal. Standing water finds its way past weatherstripping and around the frame, and you get it inside.
- The well itself. Galvanizing is sacrificial. Continuously wet, buried in clay, it goes from the soil side first — which is why a well can look fine from inside and be perforated behind.
- The foundation. Persistent hydrostatic pressure against the wall next to an opening is the worst version of this and the reason not to leave it for another season.
Order of operations
- Check the downspouts first. Free, and it is the cause more often than people expect.
- Check the grade around the well. Cheap to fix, fixes the side-water case entirely.
- Then look at the base. If it holds water with no rain, the base is the problem and a cover will not help.
- Fit a cover once the well drains, to keep what you fixed working — steel or aluminum.
If the well is rusted through at the base while you are down there, replace it rather than rebuilding around it. The steel is the cheapest part of the job and the only part you are not paying labour for twice.