An election pursuant to Section 16648 is effective with respect to all taxes levied and assessed after February 1 next succeeding the date upon which the certified copy is filed. Thereafter all assessments shall be made and taxes collected by the assessors or tax collectors of the counties in which the district is situated until the board by ordinance elects otherwise. When the board elects otherwise, a certified copy of such ordinance shall be filed with the auditors of the counties in which the district is situated and it is effective with respect to all taxes levied and assessed after February 1st next succeeding the date upon which the certified copy is filed.