There is one demographic that isn't thrilled with the population growth in the Sunbelt: the people that already live there. Population growth throughout the region has triggered new apartment development, particularly in the suburban markets, but many projects are getting stalled or altogether shut down during City Council approvals as residents push back against growth, with overcrowding in schools, increased traffic and building height among the top issues.

"People tend to view the South as being more business friendly and more builder friendly, but when you get to the suburbs, the NIMBYism is real. It is very challenging to get the approvals to build. In some cases, the further out you go, the more challenging it is," Jeremy Katz, co-head of CP Capital, tells GlobeSt.com. "Those suburban communities tend to be opposed to multifamily construction."

Over the last two years, many of the popular metros have experienced record rent growth, many with double-digit increases. According to Katz, it's a model economic problem: more people means there is a need for more housing. Without new development, rents will continue to escalate. "Even today where you have some of these towns advocating for more housing and more affordable housing, when push comes to shove and it goes to City Council, everything can come to a grinding halt. Sometimes projects die altogether and sometimes projects get dragged out," says Katz. "That serves as an artificial limiter on the amount of apartments that can get built, even though there is a need for them."