Rentability of single family homes

Hello all, I was trying to do some research regarding how rentable single family homes are in the Waco area, specifically In Hewitt. I found some properties listed for over 50 days and still not rented out. Is there anywhere I can find information regarding the likelihood of a single family home renting out in a certain area? **other than going on Trulia or Zillow and looking at how long rental properties have been listed for** Thanks for your help!