New Apartment building

[Sid N.]

I am eyeing a lot in east bay area to build a multi family on a busy street .  the lot is 3000 sq ft and building can go upto 65 ft in height .

how do I know what sq footage can i build ?  Also being in down town i am assuming the utilities would not much much of the cost .

Asking the experts here .. any other warning signs I should be checking so that i don't get surprised after i purchase ?