427B.5  Exemption may be repealed.
  When in the opinion of the city council or the county board of supervisors continuation of the exemption granted by this chapter ceases to be of benefit to the city or county, the city council or the county board of supervisors may repeal the ordinance authorized by section 427B.1, but all existing exemptions shall continue until their expiration.
[C81, §427B.5]