N.J. Stat. Ann. § 40:73-9

In any borough governed under the commission form of government law and having a population of less than 5,000 inhabitants, any person holding the office of borough tax collector, borough treasurer or both borough tax collector and borough treasurer need not be a resident of the borough notwithstanding the residency requirements prescribed by N.J.S. 40A:9-1 or by any other law. Any waiver of residency requirements for any of the aforesaid offices shall be contingent upon the adoption of a municipal ordinance to that effect.