Basis of inherited property

[Jon Pinkerton]

My wife inherited her mothers home when she passed in October 2017.    The home is going to become a rental property.   I understand that the basis on which depreciation will be calculated is based on the fair market value at the time of her passing.     Can I use the zillow zestimate as the basis?   Looks to be pretty accurate and I can look back in time to get a value?