A use lawfully occupying a structure or site that does not conform with, and which pre-existed, regulations or the site area regulations for the zone in which the use is located shall be deemed to be a non-conforming use and may be continued, except as otherwise provided in this chapter.

A structure, lawfully occupying a site that does not conform with, and which pre-existed, the standards for front yard, side yards, rear yard, height, coverage, or distances between structures for the zone in which the structure is located, shall be deemed to be a nonconforming structure and may be used and maintained, except as otherwise provided in this chapter.

A sign, outdoor advertising structure, or display of any character, lawfully occupying a site, that does not conform with, and which pre-existed, the standards for subject matter, location, size, lighting, or movement prescribed for signs, outdoor advertising structures, and displays for the zone in which it is located shall be deemed to be a nonconforming sign and may be displayed and maintained, except as otherwise provided in this chapter.

Routine maintenance and repairs may be performed on a structure or site, the use of which is nonconforming, on a nonconforming structure, and on a nonconforming sign.

No structure, the use of which is nonconforming, and no nonconforming sign, shall be moved, altered, or enlarged unless required by law, or unless the moving, alteration, or enlargement will result in the elimination of the nonconformity, except as permitted in this chapter.

No nonconforming use shall be enlarged or extended in such a way as to occupy any part of the structure or site of another structure or site which it did not occupy at the time it became a nonconforming use, or in such a way as to displace any conforming use occupying a structure or site, except as permitted in this chapter.

No nonconforming structure shall be altered or reconstructed so as to increase the discrepancy between existing conditions and the standards for front yard, side yards, rear yard, height of structures, or distances between structures, or usable open space prescribed in the regulations for the zone in which the structure is located. Additions to existing nonconforming structures, including second story additions, may be permitted provided the new addition does not further encroach into the nonconforming setback area beyond the extent of the existing structure, or exceed the height limitation for the zone in which the structure is located, and must comply with all other requirements of the Municipal Code. Said encroachment shall be limited to an extent equal to or less than 50 percent of the length of the portion of the existing structure that projects into the required setback as described below and as depicted in Figure 18.34-1:

No use which fails to meet the performance standards of the zone in which it is located shall be enlarged or extended or shall have equipment replaced that results in failure to meet performance standards unless the enlargement, extension or replacement will result in elimination of nonconformity with performance standards.

Whenever a structure which is located in any commercial or industrial zone which does not comply with the standards for the front yard, side yards, rear yard, height of structures, or distances between structures prescribed in the regulations for the commercial or industrial zone in which the structure is located, or the use of which does not conform with the regulations for the commercial or industrial zone in which the use is located, is destroyed by fire or other calamity, by act of God, or by the public enemy to the extent of 50 percent or less, the structure may be restored and the nonconforming use may be resumed; provided, that restoration is started within one year and diligently pursued to completion. When the destruction exceeds 50 percent or the structure is voluntarily razed or is required by law to be razed, the structure shall not be restored except in full conformity with the regulations for the commercial or industrial zone in which it is located and the nonconforming use shall not be resumed.

When a structure is located in a residential zone and the use of which does not conform with the regulations for a residential zone in which it is located by virtue of its use being commercial or industrial is destroyed by fire or other calamity, by act of God, or by the public enemy, to the extent of 50 percent or less, the structure may be restored and the nonconforming commercial or industrial use may be resumed, provided that restoration is started within one year and diligently pursued to completion. When the destruction exceeds 50 percent or the structure is voluntarily razed or is required by law to be razed, the structure shall not be restored except in full conformity with the regulations for the residential zone in which it is located and the nonconforming commercial or industrial use shall not be resumed.

The extent of damage or partial destruction shall be based upon the ratio of the estimated cost of restoring the structure to its condition prior to such damage or partial destruction to the estimated cost of duplicating the entire structure as it existed prior thereto. Estimates for this purpose shall be made by or shall be reviewed and approved by the Building Official and shall be based on the minimum cost of construction in compliance with the Building Code.

In any zone, a residential use, provided that the number of dwelling units shall not be increased.

In an R zone, a nonresidential use that is a permitted use or a conditional use in the C-O or C-N zone may be continued and a conditional use permit may be granted for expansion of the floor area or the site area occupied by the use by not more than 10 percent in any five-year period.

In any C-G zone, a use that is a permitted use or a conditional use in any C zone or any M zone may be continued and a conditional use permit may be granted for expansion of the floor area or the site area occupied for the use by not more than 10 percent in any five-year period.

In an M zone, a use that is a permitted use or a conditional use in any M zone may be continued, provided that nonconformity with screening and performance standards requirements shall be eliminated as prescribed in Table 18.34-1. A conditional use permit may be granted for expansion of the floor area or the site area.