All structures and uses not conforming to the
regulations of the district in which they are located at the time
of adoption of this chapter shall be known and regarded as "nonconforming."
A nonconforming structure or use may not be
altered, rebuilt or resumed except in conformity with the regulations
for the district in which it is located if:
A. Either a nonconforming structure or nonconforming
use has once been changed to a conforming use.
B. A nonconforming use of land has ceased for any reason
for a period of more than 60 days.
C. A nonconforming use of a structure has ceased for
any reason for a consecutive period of six months or for 18 months
during any three-year period.
D. A nonconforming structure is destroyed by any means
to the extent of 60% or more of either its value or its bulk.
Whenever the boundaries of a district shall
be changed so as to transfer an area from a district of one classification
to a district of a different classification, the foregoing provisions
shall apply to nonconforming uses created by such transfer.