New flooding in basement of Jersey City brownstone. No flood zone. What to do?

[Mike Bower]

Hey BP Community,

I own a condo in a downtown Jersey City brownstone close to Grove Street. The building is not in a flood zone and has no history (that I'm aware of) of flooding in the past 2.5 - 3 years I've owned it.

This morning, I went into the basement and found 2-3" of flooding. I spoke with the commercial unit employees that rent out the bottom floor, and they said the flooding came from yesterday's rain and was the worst flooding they've seen to date. At the worst point, it was anywhere from 4-6". They're now using a small, low-power handheld pump to get the water out onto the street. This is confusing to me, because rain over the last few days didn't strike me as that heavy, and we've definitely seen much worse rain recently without this flooding.

Question for the community: with no particular history of flooding, why would a light rain from the last 2 days cause a dramatic increase in flooding in the building's basement? Could something have changed in the foundation, or the area surrounding the building? I'm stumped as to what would cause this change.

For extra context, this same commercial unit renter also previously had issues with a leak from the plumbing of their soda machine, which flooded one of the other condo unit owner's storage room in the basement as well. I'm starting to wonder if the commercial unit had another flood from their plumbing issues and is blaming it on the rain so as to avoid liability for repairs.

Given the info on hand, how would you go about addressing this? Do I need to get an inspector in to look where the flooding could have come from? Or a water damage / mold remediation company?

Would appreciate any advice, as I'd rather the building spend some money now to protect the foundation and its financial future than sweep it under the rug and cause bigger issues down the line.

Thank you -