Any nonconforming use, building or structure which existed lawfully at the time of enactment of this chapter may be continued subject to the regulations which follow in this article.

The nonconforming use of land shall not be enlarged or extended beyond the area of land occupied by such use at the time of the adoption of this chapter. A nonconforming use of land may not be moved in whole or in part to any other portion of the lot or parcel of land occupied by such nonconforming use at the time of adoption of this chapter. A nonconforming use of land shall not be changed to another nonconforming use. If a nonconforming use of land is discontinued for a period of 12 consecutive months, it shall not be renewed, and any subsequent use of the land shall conform to the regulations of the district in which the land is located.

A building occupied by a use which does not conform to the use regulations enumerated in Article IV shall not be added to or enlarged in any manner unless the use thereof is made to conform to all the regulations of the district in which it is located. A building occupied by a conforming use but not conforming to other regulations of the chapter may be added to or enlarged if the proposed addition or enlargement does not increase the degree of nonconformity.

No structural alterations shall be made to any building occupied by a nonconforming use unless such alterations are required by law: provided, however, that such maintenance and repairs as are required to keep said building or structure in sound condition shall be permitted. Alterations and repairs intended and designed to decrease or eliminate nonconformance to the provisions of this chapter shall be permitted.

A nonconforming use of a building may not be changed except to a conforming use or to a use that decreases or eliminates nonconformance to the provisions of this chapter. When so changed, such nonconforming use or any use which increases nonconformance with the provisions of this chapter may not be resumed thereafter.

A nonconforming use of a building or structure or any portion thereof which is discontinued for a period of 12 consecutive months shall not be reestablished, and any subsequent use shall conform to the use regulations of the district in which the premises is located. A use shall be deemed to have been discontinued under any of the following conditions:

A nonconforming use may not be extended to any other part of such building.

A building devoted to a nonconforming use destroyed or damaged by fire, wind, explosion, structural failure or other natural cause to the extent less than 75% of its true value at the time of such damage, as adjusted from assessed value, based upon State Board of Equalization rates, may be replaced, provided that application for a building permit is made within three months subsequent to the date of such damage or destruction, and further provided that such restoration shall be diligently carried out and completed within a time specified by the Common Council. A building devoted to a nonconforming use destroyed or damaged by fire, wind, explosion, structural failure or other natural cause to an extent greater than 75% of its true value at the time of such damage, as adjusted from assessed value, based upon State Board of Equalization rates, shall not be rebuilt except in conformity with the regulations of the district in which such use is located.

If any building in which any nonconforming use is conducted is hereafter removed, the subsequent use of the land on which such building was located and the subsequent use of any building erected thereon shall conform with the regulations of the district.

Any building for which a permit has been lawfully granted and on which the construction has been stated and diligently prosecuted before the effective date of this chapter may be competed.