A.   Use Of Building Or Land: Any lawfully established use of a building or land, at the effective date hereof or of amendments hereto, that does not conform to the use regulations for the district in which it is located shall be deemed to be a legal nonconforming use and may be continued, except as otherwise provided herein. (1996 Code app. A § 6.1-1)

   B.   Nonconforming Building Or Structure: Any legal nonconforming building or structure may be continued in use, provided there is no physical change, other than necessary maintenance and repair, except as otherwise permitted herein. (1996 Code app. A § 6.1-2)

   A.   Change To Conforming Use: Whenever any part of a building, structure or land occupied by a nonconforming use is changed to or replaced by a use conforming to the provisions of this title, such premises shall not thereafter be used or occupied by a nonconforming use, even though the building may have been originally designed and constructed for the prior nonconforming use. (1996 Code app. A § 6.2-1)

   B.   Abandonment Of Use:

      1.   Whenever a nonconforming use of a building or structure, or part thereof, has been discontinued for a period of twelve (12) consecutive months or for a continuous period of eighteen (18) months if the building was originally designed and constructed for a nonresidential use, or whenever there is evident a clear intent on the part of the owner to abandon a nonconforming use, such use shall not, after being discontinued or abandoned, be reestablished, and the use of the premises thereafter shall be in conformity with the regulations of the district. (1996 Code app. A § 6.2-2)

      2.   Where no enclosed building is involved, discontinuance of a nonconforming use for a period of six (6) months shall constitute abandonment. (1996 Code app. A § 6.2-3)

   C.   Nonconforming Use Prior To Effective Date Hereof: A nonconforming use not authorized by the provisions of city ordinances in effect at the effective date hereof shall be discontinued and not reestablished, except if the provisions of this title find the use to be conforming to the district in which it is then located. (1996 Code app. A § 6.2-4)

   A.   A nonconforming use of a building or structure, or part thereof, may be changed to a use of the same or of a more restricted character, but may not thereafter be changed to any less restricted use. (1996 Code app. A § 6.3-1)

   B.   Any part of a building, structure or land occupied by a nonconforming use which is changed to or replaced by a use conforming to the provisions of this title shall not thereafter be used or occupied by a nonconforming use. (1996 Code app. A § 6.3-2)

   A.   Normal maintenance of a building or other structure containing a nonconforming use is permitted, including necessary nonstructural repairs and incidental alterations which do not extend or intensify the nonconforming use. (1996 Code app. A § 6.5-1)

   B.   No structural alterations shall be made in a building or other structure containing a nonconforming use, except in the following situations:

      1.   When the alteration is required by law.

      2.   When the alteration will actually result in eliminating the nonconforming use.

      3.   When a building containing residential nonconforming uses may be altered in any way to improve livability, provided no structural alteration shall be made which would increase the number of dwelling units or the bulk of the building. (1996 Code app. A § 6.5-2)

If a building or other structure containing a nonconforming use is damaged or destroyed by any means to the extent of fifty percent (50%) or more of its replacement value at that time, the building or other structure can be rebuilt or used thereafter only for a conforming use and in compliance with the provisions of the district. In the event the damage or destruction is less than fifty percent (50%) of its replacement value, based upon prevailing costs, the building may then be restored to its original condition, and the occupancy or use of such building may be continued which existed at the time of such partial destruction. In either event, restoration or repair of the building or other structure must be started within a period of one year and diligently prosecuted to completion. (1996 Code app. A § 6.6)

   A.   A nonconforming building may be enlarged or extended only if the entire building is thereafter devoted to a conforming use and is made to conform to all the regulations of the district in which it is located. (1996 Code app. A § 6.7-1)

   B.   No building partially occupied by a nonconforming use shall be altered in such a way as to permit the enlargement or expansion of the space occupied by such nonconforming use. (1996 Code app. A § 6.7-2)

   C.   No nonconforming building in any residential district shall be so altered as to increase the number of dwelling units therein. (1996 Code app. A § 6.7-3)

   D.   No nonconforming use may be enlarged or extended in such a way as to occupy any required usable open space, or any land beyond the boundaries of the zoning lot as it existed at the effective date hereof, or to displace any conforming use in the same building or on the same parcel. (1996 Code app. A § 6.7-4)

Wherever a lawfully existing building or other structure otherwise conforms to the use regulations of this title, but is nonconforming only in the particular manner hereinafter specified, the building and use thereof shall be exempt from the requirements of section 11-10-4 of this chapter: (1996 Code app. A § 6.8-1; amd. 2010 Code)

   A.   In any R district, where a dwelling is nonconforming only as to the number of dwelling units it contains, provided no such building shall be altered in any way so as to increase the number of dwelling units therein.

   B.   In any R-5 district, where a use permitted in the B-1 district occupies ground floor space within a multiple-family dwelling located on a corner lot.

   C.   In any B or M district, where the use is less distant from an R district than that specified in the regulations for the district in which it is located. (1996 Code app. A § 6.8-1)