Except as otherwise provided in this chapter, the lawful use of land or buildings existing on the date of the adoption of this chapter may be continued although such use of building does not conform to the regulations specified in this chapter. However, the following provisions shall apply to all such nonconforming uses:

Discontinuance. In any district, whenever a nonconforming use of land, premises, building or structure, or any part or portion thereof, has been discontinued for a period of 365 consecutive days, such nonconforming use shall not be reestablished, and all future uses shall be in conformity with the provisions of this chapter. Such discontinuance applies to all active and continuous operations of a nonconforming use, or a part or portion thereof, regardless of any lack of intent to abandon the same or regardless of intent to resume active operations at a later date. If actual abandonment in fact is evidenced by the removal of buildings, structures, machinery, equipment and other evidences of such considered to be completed, and all rights to reestablish or continue such nonconforming use shall thereupon terminate.

A nonconforming building may not be reconstructed or structurally altered during its life to an extent exceeding in aggregate cost 50% of the assessed value of the building, unless said building is changed to conform to the requirements of this chapter.

Changes. Once changed to a conforming use, no building or land shall be permitted to revert to a nonconforming use.

A residential lot existing at the time of passage of this chapter which is less than the required area or width or cannot meet the required front setback for any residential use in the district and was owned or under contract for purchase by persons other than those owning or leasing adjoining lots at the time of adoption of these regulations may be used for residential purposes, provided that the lot has a front setback equal to at least 60% of the required minimum and that minimum side and rear setback requirements can be met.

A commercial lot existing at the time of passage of this chapter which is less than the required area or width or cannot meet the required front setback for any commercial use in the district and was owned or under contract for purchase by persons other than those owning or leasing adjoining lots at the time of adoption of these regulations may be used for commercial purposes, provided that the lot has a front setback equal to at least 60% of the required minimum and that minimum side and rear setback requirements can be met.