The proceedings of any local agency which has, prior to the effective date of this section, adopted by ordinance or resolution, and received voter approval of, a standby or availability charge pursuant to statutes repealed by the act which enacted this section, shall be deemed to be in compliance with the provisions of Section 53978. The local agency may levy such assessment pursuant to the provisions of such ordinance or resolution for all fiscal years following the effective date of this section pursuant to Section 53978.