When your basement window is near ground level, there’s a chance that during a heavy rain storm, water could enter in around the edges. During the winter, snow can build up around your basement window and when there is a mild winter rainy day in January or February, there is no where for the water to drain to because the ground is frozen. The same happens in the spring when the snow melts, water can enter into the basement through the window.
Window wells are necessary when the basement window is lower than the earth (ground level) outside. For example, if you want to increase the slope of your exterior ground level around your house to help for drainage, and there is a window at ground level, you will need to install a window well. The purpose of a window well is to have a place where water can drain too and 3/4 inch crushed gravel is used for water to flow. In the past, if there was 16 to 24 inches of crushed gravel, that was considered enough for a proper window well installation. However, with global warming and our increasing number of flash floods we have each year, even at 24 inches there is not enough space for all the water. That is why we install a horizontal french drain that connects directly to your existing french drain that is around your house. Even on older homes where there may not be a french drain, the fact that there is a larger space for water to gather, means you don’t ever have to worry about those crazy rain storms anymore.