Hi, to my understanding is 24 months. I have been told that could be exceptions, case by case.
Did you know that NACA only pre approves the loan? Final approval will be done by the "real" investor.
At the final stages of the purchase, you will need to provide update documentation, from cancel rent checks to bank statements, paystubs and anyhting else required by the investor.
NACA program requires rental verification of 12 months and from that information, seasoing has to be more than 12 months.