Fla. Stat. § 373.316

No well in existence on the effective date of this part shall be required to conform to the provisions of s. 373.313 or any rules or regulations adopted pursuant thereto. However, any well now or hereafter abandoned or repaired as defined in this part shall be brought into compliance with the requirements of this part and any applicable rules or regulations with respect to abandonment of wells, and any well which is determined by the department to be a hazard to the groundwater resources must comply with the provisions of this part and applicable rules and regulations within a reasonable time after notification of such determination has been given.