A nonconforming land use or structure is one which existed lawfully on the date this chapter or any amendment thereto became effective, and which fails to conform to one or more of the applicable regulations of this chapter or such amendment thereto, except minimum lot area, yard and setback requirements.

A nonconformity shall not be deemed to have existed on the date this chapter or any amendment thereto became effective, unless:

The nonconforming use of open land for storage purposes and advertising signs and bulletin boards shall be discontinued within two years of their becoming nonconforming.

An existing nonconforming land use or structure shall not cause further departures from this chapter. Although an existing nonconformity may be continued except as herein limited, it may not be changed to another use except a use permitted in the district in which it is situated, provided it complies with the requirements of that district.

A nonconforming use shall not be enlarged, extended or altered and a structure or part thereof devoted to a nonconforming use shall not be enlarged, extended, constructed, reconstructed or structurally altered, except:

The restoration of any structure and its use, when such structure has been damaged by fire, explosion, act of God or the public enemy to an extent less than sixty percent of its replacement value at the time of destruction, may be permitted, provided the restoration of such structure and its use in no way increases any former nonconformity; and provided, further, that restoration of such structure is begun within six months of such damage an diligently prosecuted to completion within two years following such damage. Where damage to the structure is more than sixty percent of the replacement value at the time of damage, the structure shall not be restored except in full conformity with all the regulations of the district in which such structure is situated. However, none of the restrictions contained in this section shall limit the authority of the board of adjustment to grant relief for reconstruction of a nonconforming use if it finds some compelling public necessity requiring the continuance of the nonconforming use and the primary purpose of continuing the nonconforming use is not to continue a monopoly.

In the event that a nonconforming use of any building or premises is discontinued for a period of two years, the use shall be deemed abandoned. Thereafter, the use of such building or premises shall conform to the uses permitted in the district in which it is located.