does this sound good and whats my ROI

[Gino Cook]

I'm looking to buy a 4 family for $75,000 hear is all the info with numbers I came up with not actual real numbers but the taxes and rents 

purchase $75,000

down payment $1500

balance $60000

taxes $650 a little high 

payment $250

interest $300

insurance $200

water sewer $200 they pay all other utilities 

maintenance $150

total cost per month $1750

total rents $2600 and that could really go up to $2800 but I kept it low 

total cash flow $850 a month 

Does it look like i'm missing anything for operating cost ? what would my ROI be on this ? also I could possibly add a 5 apartment in this home from what the listing says but I just went with numbers from a 4 family . Tenants pay all utilities but water and sewer .