Wash DC income & property tax question - out of state investor

[Mary Joe]

Hi All

I live in NY, am thinking of purchasing a rental property in DC.  

2 questions:

1) Do I need to file a separate tax return to DC ?   I will of course include this rental property in my 1040 and my NY return, but not sure if there is a separate return that I also need to file to DC for the rental property. 

2) How can I find out how much more in property tax I will be paying if the property is not owner occupied and I am from out of state?  I read it somewhere that if the property in DC  is my primary residence, I can benefit from approx $70K in reduction from the property's assessed value.    Is that the only difference as far as ppty tax is concerned for owner occupied vs out of state investor ownership?

Any advice would be appreciated.

MJ