N.J. Stat. Ann. § 40:62-105.4

At the first meeting of the board of water commissioners elected in any newly created district the members of the board shall divide themselves by lot into three classes; the term of the two members composing the first class shall be vacated at the expiration of the first year; the term of the two members composing the second class shall be vacated at the expiration of the second year, and the term of the one member composing the third class shall be vacated at the expiration of the third year, so that after the first election two members of the board of water commissioners shall be elected annually, except every third year when but one member shall be elected, all of whom shall hold office for three years and until their successors are elected.