[Retric]

> why they'd classify it as flooding

As you mention water seeping into the basement is one common issue but even without that there are a few more.

EX: Someone sets up a garden with a small earthen wall. They get ~6 inches of rain which seems insane for the area which due to poor drainage pools behind the earthen wall until the weight of water bursts the wall. Followed by a wave of water causing surprising amounts to dammage.

The insurance adjuster then says sorry this was caused by standing water not wind / rain.

The important point is drainage issues are generally classified as flooding as are mud slides.