(2) When the petition or resolution proposing formation provides for a five-member board for the water authority, the terms of three of the members first elected to the board shall expire on June 30 next following the date of the first regular district election in the water authority. The terms of the remaining two members shall expire on June 30 next following the date of the second regular district election in the water authority. When the petition or resolution proposing formation provides for a seven-member board for the water authority, the terms of four of the members first elected to the board shall expire on June 30 next following the date of the first regular district election in the water authority. The terms of the remaining three members shall expire on June 30 next following the date of the second regular district election in the water authority. [1987 c.863 §6; 1993 c.577 §23]