New jersey beginner landlord certificate of occupancy

[Eric Dea]

I currently live in Brick, new Jersey (Ocean county) and I've been house hacking for the last few years having had a roommate living with me in my extra bedroom paying me rent. Now I'm ready to move on and buy another property, my current roommate wants to continue renting the whole house from me. 

My questions is, since he is the current resident and not a new tenant moving in do I still need to go through the CO process? I looked on my city's website for rentals and the first item on the check list for inspection is that the unit must be vacant. What issues can arrise if I do not have a CO? 

Any help would be appreciated!