Earlier quoted context omitted.
$1,400 isn't going to get you your dream apartment, but it's a reasonable budget for a one bedroom apartment that's in DC and not in a bad neighborhood. It's also pretty common to live outside the city and commute in on Metro (DC's Metro is built more like a commuter rail than a urban subway system).
I wouldn't say 1.4k is a reasonable rent in DC, not in my experience at least. Not even if you move out to the nearby suburbs.
I think the tricky part is that there really aren't many apartment buildings in DC to begin with, aside from the recently built and very overpriced luxury condo conversions, so the supply of one bedroom apartments is low. If you can stand to have roommates, you're much better off with a 2 bedroom English basement or a 3-4 bedroom little rowhouse.