Perhaps is sits on an area that was an old local drainage and the ground is slightly more pervious allowing the local ground water to collect and move down gradiant until it hits this house's basement.One thing that puzzles me is the why the existing sump pump is not dealing with the issue.

However, a piece of the puzzle we can't see from the post is the neighborhood/area/geography.

Free knowledge is great AS LONG AS you piece the full puzzle together and utilize it all.   

I am puzzled as to why this apt isn't selling fast... it's priced at $2300/m and is 2000 square feet.

Locating a good zip code or neighborhood is just one piece of the puzzle .Are these people that live in your same city ?

My dad is a real estate attorney who never invested a day in his life...puzzles the hell out of me!

Juat really havent put the puzzle together and its difficult.

Estimate costs, and start putting together your puzzle.

In REI, the house makes absolutely no difference, which takes me to the next, and most important part of the 'puzzle'...- Make sure your numbers work!

Another piece of the puzzle is that the property is actually 3 lots, with houses on two of them.