173.06 COMPLIANCE AND AMORTIZATION OF NONCONFORMING SIGNS.
      1.   Conformance Required. Except as may be hereinafter specified, no sign shall be erected, placed, maintained, converted, enlarged, reconstructed or structurally altered which does not comply with all of the regulations established by this chapter.
      2.   Maintenance. All signs shall be maintained in a good state of repair, including, but not limited to, the structural components, the lighting, if any, the portion attaching the sign to the ground or structure, and the surface features.
      3.   Nonconformance and Amortization of Premise Identification Signs. Where a sign exists at the effective date of adoption or amendment of the ordinance codified in this chapter that could not be built under the terms of this chapter by reason of restrictions on area, use, height, setback, or other characteristics of the sign or its location on the lot, such sign may be continued so long as it remains otherwise lawful, subject to the following provisions:
         A.   No such sign may be enlarged or altered in a way which increases its nonconformity; however, reasonable repairs and alterations may be permitted.
         B.   Should such a sign be destroyed by any means to an extent of fifty percent or more of its replacement cost at time of destruction, it shall not be reconstructed except in conformity with the provisions of this chapter.
         C.   Within any zoning district, all premise identification signs or other signage that pertains to the premises on which such sign is located, shall comply fully with the provisions of this chapter, unless otherwise provided, within fifteen years after the effective date of this chapter. This amortization provision does not apply to outdoor advertising signs, provided that such signs remain in continuous use. Any nonconforming outdoor advertising sign that remains unused for a continuous period of 180 days shall forfeit its right to continue as a nonconforming use.