What the well is there for
When a basement window sits partly below the ground outside, something has to hold the dirt back from the glass. That is the window well. It is a liner of corrugated metal or molded plastic set against the foundation, with an open pocket in front of the window and a bottom that should let water soak away.
Older Des Moines houses often have small basement windows near the top of the wall, some with old wells and some with none at all. Newer houses have bigger wells, and a basement bedroom needs a large egress well with a way to climb out. They all leak the same way. Water collects in the pocket faster than it can drain, rises to the window, and finds the gap around the frame.
How the water gets into the well
Some of it is rain falling straight in. A well is an open hole, and in a summer thunderstorm it catches everything that falls over it. That much should drain off on its own. The trouble is the extra water.
Roof water is the big one. If a gutter overflows or a downspout empties near a window well, the well takes the runoff from part of the roof. Then there is the yard. If the ground slopes toward the house, water running across the lawn drops into the well on its way. And Des Moines clay is slow to soak anything up, so the gravel at the bottom of a well can only drain as fast as the clay under it allows.
Winter adds snow. Snow drifts into open wells and gets shoveled into them off the walk. In spring it melts while the ground under the well is still frozen, and that water has nowhere to go but up the window.
A drain that is missing or plugged
The bottom of a window well should be a layer of gravel that lets water soak down and away, sitting lower than the bottom of the window. In some houses a pipe also runs from the bottom of the well down to drain tile along the footing, so water in the well has a way out. Many older wells have neither. Their bottom is plain clay or dirt, and it holds water like a dish.
Even a good bottom stops working when it fills up. Leaves, dirt washed in from the yard and grass clippings settle into the gravel and seal it over. A drain cap gets buried. A drain pipe fills with silt or roots. Then a well that drained fine for years starts holding water after every storm.
Drain tile along the footing is a separate job from the well. If you think yours is plugged or missing, ask Joe about it.
Leaves, snow and junk in the bottom
Things collect in a window well. In the fall, leaves blow in and pack down into a wet mat. Toys, trash and dead plants end up in there too. All of it holds water against the window and keeps the gravel from draining.
Cleaning out every window well in the fall, and again once the snow is gone, costs nothing and keeps a lot of water out of a basement.
A well that sits too low
The top edge of a window well should stand up above the ground around it, so water running across the yard goes around the well instead of into it. Over the years that edge disappears. New mulch goes into the beds every spring, sod gets laid, dirt gets added, and the yard creeps up until the top of the well is level with the ground or under it.
Once that happens, the well is a drain for the whole flower bed. You can usually spot it right away. The dirt or mulch is up to the rim, and there is a muddy fan of silt inside the well where water has run in. The fix is pulling the ground down and sloping it away, or setting the well higher.
Rusted, crushed or pulled away
A lot of older window wells are metal, and metal buried in wet clay rusts. It goes first at the bottom and along the edges where the well meets the wall. Once it rusts through, dirt washes in through the holes and the well slowly fills with mud.
Wells also get bent by mowers and snow blowers, and pushed in by the ground itself, and they pull away from the foundation. A gap between the well and the wall lets water run straight down the outside of the foundation beside the window. Inside, that shows up as a wet spot below the window that is not coming through the window at all.
The window at the bottom of it
Water in the well finds the weakest point around the window. On old basement windows that is often a wood frame that has rotted, a steel frame rusted at the sill, or caulk that dried out and cracked long ago. Even a well that drains fine can leak in a hard storm if the window frame is gone.
Swapping an old basement window for a new one in the same opening is a separate question. If yours is rotted or rusted, ask Joe about it when he looks at the well.
What you can check yourself
Most of this takes a flashlight, a bucket and a few minutes per well.
- Look in each well after a hard rain and see which ones hold water and for how long
- Pull out leaves and trash, and look at the gravel underneath
- Check that the gravel sits lower than the bottom of the window
- Look for a drain cap in the bottom and clear it if you find one
- Pour a bucket of water into a dry well and watch how fast it goes down
- Check that the top of the well stands above the ground around it
- Look up at the gutter over the well and find the nearest downspout
- Look at where the well meets the wall for gaps and rust
Covers
A clear cover over the well keeps out leaves, snow and most of the rain and still lets light into the basement. For a lot of wells that is a big help. A cover needs to fit the well and sit tight, or water runs in at the edge.
Over an egress well, the cover has to open easily from inside so someone can get out. The city sets the rules for egress wells and covers, so ask the City of Des Moines about permits and what is allowed.
When a well needs to be replaced
Cleaning and regrading fix a lot of wells. But a well that has rusted through, is crushed, has pulled away from the wall, or is too small or too low for the window needs to come out. Replacing a well generally means digging out around it, setting the new well against the foundation, putting a gravel bottom in, backfilling, and sloping the ground away.
JC Cement puts in and replaces window wells in Des Moines. Joe Gomez also does basement waterproofing, so if water has been getting into the wall around the window, he looks at that too. The window wells page covers that work. Call or text Joe at (515) 777-5018 with a photo looking down into the well and one of the window from inside.