Cal. SHC § 2808.6

This division does not apply to proceedings, whether commenced before or after January 1, 1985, for repairing, restoring, rebuilding, rehabilitating, or modernizing existing public facilities when there are over 12 resident voters within the area proposed to be assessed and when the engineer of the jurisdiction undertaking assessment proceedings has determined that the work is necessary for reasons of public safety or to avoid substantially larger future costs due to deterioration and obsolescence of the public facilities involved. The determination shall be given in writing and included in the minutes of the legislative body conducting the assessment proceedings, and this section shall apply only if the necessity is found to exist by resolution adopted by the affirmative vote of four-fifths of the members thereof. The findings and determinations made by the legislative body pursuant to this section shall be final and conclusive upon all persons in the absence of actual fraud.