Non-Renewal Notice in Iowa

[Todd S.]

I have a single family house in Iowa, I'm considering giving this tenant a non-renewal notice of lease.  The Lease states that after the initial term of lease (1 year) it goes month-to-month.  I've done this several times in the past without any issues until recently I've heard from another property manager in Des Moines (large property management company), that if you plan to give someone a non-renewal you have to document and or have reasons?  

In the past I've operated until the assumption that no reason was necessary - simply give the tenant a written 30 day notice.  

I'm curious how others have handled this process?

Thanks,

Todd