There are several causes of basement flooding, including:
Heavy rain or snowfall, which can overwhelm drainage systems and cause water to seep into basements through cracks in foundations or walls.
Poorly functioning or clogged gutters and downspouts, which can cause water to pool around a building's foundation.
A high water table, which can cause water to seep into basements through the floor or walls.
Plumbing leaks, such as burst pipes or overflowing sump pumps, can cause water to flood a basement.
Overland flooding caused by overflowing rivers, streams, or lakes.
Clogged or damaged municipal sewer lines can also back up and cause basement flooding.
Improper grading of the land around the foundation can cause water to flow towards the building and into the basement.