Except as otherwise provided in this article, the lawful use of land or buildings existing at the date of the adoption of this chapter may be continued although such use or building does not conform to the regulations specified by this chapter for the zone in which such land or building is located; provided, however:

A nonconforming use shall be adjudged as abandoned when there occurs a cessation of any use or activity by an apparent act or failure to act on the part of the tenant or owner to reinstate such use within a period of three months from the date of cessation or discontinuance.

If any nonconforming building shall be destroyed by reason of windstorm, fire, explosion or other act of God or the public enemy to an extent of less than 50% of the recorded true valuation, then such destruction shall be deemed partial destruction and the nonconforming building may be rebuilt, restored or repaired within one year from the date of the destruction. If such a structure is located within the Floodplain District, the development regulations cited in § 225-22B shall be utilized to the greatest extent possible; provided, however, that if such a structure is located within the floodplain, as that area is defined in § 225-22A(1), then the requirements of § 225-22B(1)(d), as amended, must be satisfied, notwithstanding the destruction of less than or more than 50% of the recorded valuation of the structure. Nothing in this chapter shall prevent strengthening or restoring to a safe condition any wall, floor or roof which has been declared unsafe by the Building Official.

No nonconforming use shall, if once changed into a conforming use, be changed back again to a nonconforming use.

A nonconforming building may be remodeled but not enlarged or extended, unless said building is changed to a building conforming or more nearly conforming to the requirements of this chapter, and further provided that an existing eating and drinking place may add a covered patio not exceeding 1,400 square feet that is connected to the nonconforming building. In the Floodplain District, until a regulatory floodway is designated, no enlargement or extension or remodeling which would be considered a substantial enlargement shall be permitted unless the applicant has demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood more than one foot at any point within the community.

Whenever the boundaries of a zone shall be changed so as to transfer an area from one zone to another of a different classification, the foregoing provisions shall also apply to any nonconforming uses existing therein or created thereby.