Just some clarification here.
Your local real estate tax records may be acceptable for determining fmv on the date of rental.
There is a difference between the tax value, and the fair market value. Understand that you can not use the tax value, as that is traditionally 30% or more, below the fair market value. If you do use the tax value as the cost basis, then you best make sure that is "the" only value available that can be proven.
Lately I've noticed on some tax bills that they include both the FMV and the separate tax value. How the property tax appraiser comes up with an FMV on the property with a structure on it is beyond me, since the property tax appraiser never steps foot inside any structures on that property.
