(1) Nonconforming signs may be maintained subject to the following conditions:
(a) No additions or enlargements may be made to a nonconforming sign except additions or enlargements required by law.
(b) If any nonconforming sign is moved, voluntarily or involuntarily, that sign shall thereafter conform to the requirements of the sign standards as a newly constructed sign.
(c) Any sign which is constructed to replace a nonconforming sign shall be constructed in compliance with all applicable provisions of the sign standards.
(2) Whenever a nonconforming sign is damaged or destroyed to the extent of 50 percent or less of its value as of the last date of use, it may be restored and the use of the sign which existed at the time of the damage or destruction may be continued, if such restoration is started within a period of 90 days of such damage or destruction and is diligently pursued thereafter.
(3) Except as provided in EC 9.6675(7) and EC 9.6680(7) or where only a change in display copy is made, any nonconforming sign which is structurally altered or has illumination installed shall be brought into compliance with all applicable provisions of the sign standards within 90 days and shall thereafter be kept in compliance with the sign standards.
(4) Nothing in this section shall be deemed to prevent the maintenance of any sign, or regular manual changes of sign copy on a sign intended for such purposes.
(5) The provisions of subsection (2) of EC 9.6635 Approval of Permit Application do not apply to signs in existence pursuant to a validly issued sign permit as of July 1, 1990, along Goodpasture Island Road from a point 300 feet north of the intersection with Valley River Way to a point 1400 feet north of the intersection. The provisions of subsection (2) of this section shall apply except that restoration of a damaged sign shall be allowed where a sign is damaged to the extent of 100 percent of its value. All other provisions of this section shall apply.