I'm looking to purchase a home for my mother and her sister in Iowa, US. Mostly for personal reasons, but also some investment potential. The home would need to be a duplex or have separate apartments up and down.

Most duplexes in my area are too large for their needs and financial means. One option is to buy a single family home and convert to a duplex or a two apt home.

I own a home, so I'm familiar enough with the typical buying process. But what about the purchase of a home with the intent to rent? I understand its common to need more down and the %s are higher and insurance is higher...

... but what do I need to do to convert a single family home into a bldg with two or more units for rent?. not physically what needs to be done to the property, but what needs to be done with the local gov to properly classify this home as a multiple rental? How can I be assured I can do such a conversion before the purchase? Questions for the county assessors office?

Any structural issues I'm comfortable enough with, or have someone I trust to address it... it's the legal details I'm fuzzier-than-normal about. The more I look, the more I'm certain I'm likely going to need to do a conversion.

Also, any useful resources for details such as this that you've used? There are tons of books out about buying investment properties, but none I've seen cover some basic dirty details like this.

Thanks in advance.