The board may consolidate any two or more zones or abolish any zone pursuant to a resolution adopted by the board providing for such action. Before adopting such a resolution, the board shall conduct a public hearing notice of which shall be given as provided by RCW 36.32.120(7). Any indebtedness of any zone or zones which are abolished or consolidated shall not be impaired by their abolishment or consolidation, and the board shall continue to levy and collect all necessary taxes and assessments until such debts are retired. Whenever twenty-five percent of the electors of any zone file a petition, meeting the requirements of sufficiency set forth in RCW 86.15.020, asking that a zone be abolished, the board shall: (1) Adopt a resolution abolishing the zone or (2) at the next general election place a proposition on the ballot calling for a yes or no vote on the abolition of the zone.