Keep window wells free of grass-clippings, fallen leaves, and other yard debris. Accumulations of organic debris reduce window well capacity for water, which can seep into windows or leak into the foundation.
Especially if your window wells are constructed with drains, keep them clear so water is directed away from vulnerable below-ground areas.
Construct grates to reduce debris-accumulation. Cut coarse-mesh hardware cloth in pieces large enough to rest on front and side sills of your window wells, and deep enough to touch the windows behind the wells.
Debris will accumulate on these simple screens so that it does not have to be dug out of wells, while water still gets through. Because of eventual rust, use heavy gloves to move and empty screens, and be prepared to replace them after a few seasons of wear.
Preventing water damage
Cover wells that tend to flood regularly with plastic bubble covers. These durable covers let light through to below-ground windows, keeping debris and water out.
These work particularly well in areas where window wells were made narrow and shallow, intended more for light than drainage. Be certain, however, that adjoining areas provide drainage for water runoff.
Staying current with maintenance
Make it a regular seasonal practice to inspect windows protected by window wells, outside and inside. Windows exposed to below-ground moisture need regular caulking and painting to withstand water damage, rust and/or rot.
Check interior frames and adjoining walls on the same seasonal schedule to forestall possible leaks.