Then we were chatting by the elevators on the way out.

For condo investment you want low rise building no elevator/pool, door man, etc all these cost too much to maintain.

I wouldn't elevate it & probably just not interact with that neighbor. 

I got a quote for a survey to get a flood elevation certificate but its $400... not sure if thats worth it yet.

But what if you have an upstairs apartment in a three-story building with no elevator?

You can't get to my door because of the fact that there is no doorman at the building and only people with proper keys can access the lobby, elevator etc.

I bet she's paying her car payment...elevate your significance in her financial life by enforcing your lease. 

@Russell BrazilSage advice Russel Brazil.I d urge people to run scenarios on their personal finances, things like - what if they lost their jobs, had elevated vacancy rates on rentals, had to drop rents by 30 - 40%.

My suspicions were elevated when I " a friend of mine" happened to see some mail addressed to the sister being delivered to the unit in question.I stopped the sister one day and asked her point blank if she was living there now, and she said "no", that she was coming over to "hang out" and check on the place because her sister was staying with her BF.  

If you’re in a flood zone you might have to get a Elevation certificate determining the height of your home.