They may not represent a majority of the nation's largest 50 apartment markets, but 14 metro areas have experienced demand outpacing supply in the second quarter, according to RealPage.

Overall, the country absorbed more than 83,400 units between April and June, which wasn't enough demand for the completion of more than 107,400 units. But those 14 cities that did see demand outpace supply reflected a range of locations from coast to coast and in between in the Heartland.

At the top of this list of demand outstripping supply was Chicago-Naperville-Elgin, Ill.-Ind.-Wis., which had 2,488 completions and absorption of 4,062 units for a big difference of almost 1,600 units. And in an online post on Domu, an article cited how new apartments are emerging all around the city from large buildings to smaller buildings.