A window well leaking into your basement is one of the most common rainy-season calls homeowners make, and one of the most misunderstood. Most people assume the window itself is the problem and start shopping for a new one. Usually, the real problem is the water sitting outside it.
Here is the short answer. Basement windows are not designed to hold back standing water. When a window well fills up because its drainage is clogged, missing, or overwhelmed, water rises above the bottom of the window and finds its way in around the frame. Fix the water in the well, and the leak usually stops.
I am Dylan with Better Basements & Waterproofing. We find and fix basement water problems throughout Portland, Eugene, and Vancouver. Here are the five causes behind a window well leaking, and the fixes that actually work.
How a Window Well Is Supposed to Work
A window well is the U-shaped liner and dug-out space around a basement window that sits below ground level. It holds back the surrounding soil and lets light and air reach the window.
The bottom of a well is usually filled with loose gravel. Rain that falls into the well drains down through that gravel and into the soil, or into a drain pipe connected to the home’s drainage system. As long as water leaves the well faster than it comes in, the window stays dry.
Cause 1: Leaves and Debris Clog the Gravel
This is the most common reason we see a window well leaking in the fall, especially in neighborhoods with mature trees. Leaves, needles, and dirt pile up in the well and form a mat over the gravel. Water can no longer soak through, so it pools against the window.
The fix: Clear the well completely, down to the gravel. If the gravel is packed with silt, remove and replace it with clean gravel.
Cause 2: No Drain, or a Drain That Has Failed
Some wells were built with only a thin layer of gravel over compacted soil. Others have a drain at the bottom that has clogged or collapsed. Either way, water has nowhere to go during a long Portland storm, and you end up with a window well leaking every time it rains hard.
A quick test: run a garden hose into the well for a few minutes and watch how fast the water disappears. If it stands for a long time, the drainage is not keeping up.
The fix: Restore the drain. Depending on the home, that can mean a drain pipe at the bottom of the well tied into a perimeter drain or sump pump system.
Cause 3: Grading and Downspouts Send Water Into the Well
If the soil around the well slopes toward the house, or a downspout empties nearby, every storm sends extra water straight into the well. This is a frequent cause of a window well leaking on one side of the house but not the others.
The fix: Regrade so the ground slopes away from the window, and extend downspouts well away from the foundation. Read our guide on gutters and downspouts in basement waterproofing.
Cause 4: The Well Liner Has Pulled Away From the Foundation
A window well liner should sit tight against the foundation wall. Over time, soil movement can pull it away, leaving a gap where water and soil pour down beside the window.
The fix: Reset and secure the liner, and seal the joint where it meets the wall.
Cause 5: It Is Not Actually the Window Well
Sometimes a window well leaking is a symptom, not the cause. Water stains below a window can come from a crack in the foundation wall under the window, condensation, or groundwater pressure that is pushing water into the basement in several places.
Read how to tell if water is coming through your basement walls or floor and our guide on basement condensation vs water intrusion to narrow down the real source.
Do Window Well Covers Stop Leaks?
A clear window well cover can keep rain, leaves, and debris out of the well, which helps a lot during the fall. Bob Vila’s guide to basement leaks after heavy rain recommends covers for exactly that reason.
Two cautions. First, a cover does not fix a well with failed drainage. Groundwater and runoff from the soil can still fill it from below. Second, if your basement window is an emergency exit, any cover must open easily from the inside. Never install a cover that blocks an egress window.
You also do not need a branded enclosure system to stop a window well leaking. What matters is that the well drains, the grading is right, and the liner is sealed to the wall.
When to Call a Professional
Call for an inspection if the well floods even after you clean it, if water appears below more than one window, or if you also see damp walls, efflorescence, or water on the floor. Those are signs of a larger water problem around your foundation, not just one window.
Read our guide on emergency basement flooding solutions if water is coming in right now.
Frequently Asked Questions About a Window Well Leaking
Why is my window well leaking only during heavy rain?
During heavy rain, water enters the well faster than the gravel or drain can carry it away. Once the water rises above the bottom of the window, it leaks in around the frame.
Should I replace my leaking basement window?
Not until you fix the well. A new window will leak too if water keeps pooling against it.
How often should I clean my window wells?
At least once in the fall after the leaves drop, and again after any big storm that leaves debris in the well.
Can a window well be tied into my sump pump?
In many homes, yes. A drain at the bottom of the well can be connected to a perimeter drainage system that feeds a sump pump.
Get Your Window Well Leak Diagnosed
If your window well keeps flooding, we will find out whether the problem is the well, the drainage, or water entering your foundation somewhere else, and recommend only the work you actually need.
Learn more about our basement waterproofing services
Better Basements & Waterproofing serves Portland, Eugene, Vancouver, and surrounding communities in Oregon and Washington.
