The closest I have come to seeing a woman topless at a pool (and it happened to be in Ohio) was when a woman was with her husband in the hot tub at a gym, and instead of a swim suit top, she wore a gray sports bra that became completely see-through as soon as it got wet.
She noticed right away and covered up with her arms for a bit, but then she finally gave up and uncovered herself. It was just her husband, my wife, and me in the hot tub with her, so she eventually didn't mind that we could see. I stared a lot and she didn't seem to mind at all.
When she got out, she covered herself up again while she walked to the locker room, so I felt special that she let us see but no one else.
I just remember that she had a pretty large set of breasts with very small areola in comparison. Light pink, too.
That reminds me, many years ago we were at a hotel pool and a young woman with a blue swimsuit top became see through when wet, and she had tiny boobs with absolutely enormous areola and very dark...so quite opposite.
My ex-wife had a friend who wore a one-piece that was see through on top, too.