In this photo from Terryville, the water seeped in through the basement access. The water seeped in from the ground or surface outside. This is more common with properties or homes with a high-water table or close to body of water. If the water table is forced beyond it’s means, the table overflows, and goes the lowest point. Hence why the water exposure progressed into the basement from the outside. If there are access points, like a bulkhead or casement window that Is not continually maintained, you will see this happen more and more – however if there is areawide flooding this is temporary and cannot be avoided.