Investors & landlords

They are two separate units with their own entrances -- a 1st floor unit and 2nd floor unit.  Both identical.  They share a common basement and attic.

I'm not sure what you mean by "total Basis" and "Basis adjustments".  What are those?

I'm following your suggestion and entering our side (which was 2nd floor) as a new rental property.  TurboTax is now asking me:
  * the cost of the property (amount I paid for it)
  * the cost of the land
  * date purchased or acquired

I have no idea what the cost of the land is.  What would I enter there?

I do know the amont I paid for the duplex and date I acquired it.  But, would I actually enter the purchase price and date for the entire duplex even though I already have this entered for the "old side"?

Or should I enter the date this unit was put in service (Jan 2018)?