@Michael Toba.
Hi Michael, Welcome to the site, Stony Brook has cracked down in recent years on illegal apartments and rentals (not to say that is what yours would be) to deal with what they called illegal rooming houses.
I don’t own any rentals there but have looked in the past. I believe all apartments need to be registered there to be legal.
According to the stony brook site:
“A rental dwelling unit is considered legal when it has been inspected by the Chief Building Inspector or a designated employed by the town, and meets all applicable housing, sanitary, building, electrical and fire codes, rules, and regulations. Upon receipt of the approved Inspection Report, the Chief Building Inspector shall issue a rental registration valid for 15 months from the date of issuance of the temporary rental registration.”
I believe Stony Brook is within the town of Brookhaven and they may limit the number of non-related people on your lease. I’m not trying to discourage you, and would love to hear any feedback you get through the process. You may be able to get it, might not but best of luck, let us know how it goes.