Carl
Level 15

Investors & landlords

but I am wondering why you aren't reporting your property as a single rental property, since you own both sides and rent both sides.

There's pro's and con's to both ways. One example of many, is that maybe the owner lived in one unit while renting out one unit. Then later moved out and started renting the other unit. Treating each unit as a physically separate property can make the math easier in the long run, if they later moved back into one of the units, or any other number of possible scenarios that affects only one unit.