Except as otherwise provided in this chapter, the lawful use of land or building 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:

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 one year, such nonconforming use shall not thereafter be reestablished, and all future uses shall be in conformity with the provisions of this chapter. Such discontinuance of the active and continuous operation of such nonconforming use, or a part or portion thereof, for such period of one year, is hereby construed and considered to be an abandonment of such nonconforming use, regardless of any reservation of an intent not to abandon same or of an intent to resume active operations unless where compliance with this section is technically infeasible, as determined by the Code and Zoning Enforcement Officer, the nonconformance shall provide for conformity to the maximum extent technically feasible. If actual abandonment in fact is evidenced by the removal of building, structures, machinery, equipment and other evidences of such nonconforming use of the land and premises, the abandonment shall be construed and considered to be complete and all rights to reestablish or continue such nonconforming use shall thereupon terminate.

Notwithstanding any other provisions of this chapter, any automobile wrecking yard or junkyard and any billboard, advertising structure or nonconforming sign in existence in any R District at the date of enactment of this chapter shall at the expiration of three years from such date become a prohibited and unlawful use and shall be discontinued. Provided, however, that lawfully existing signs accessory to a nonconforming business or industrial building shall not be subject to this provision.

No building damaged by fire or other causes to the extent of more than 75% of its assessed valuation shall be repaired or rebuilt except in conformity with the regulations of this chapter. Nothing in this chapter shall prevent the strengthening or restoring to a safe condition any wall, floor, or roof which has been declared unsafe by the Building Inspector.

A nonconforming use shall not be extended, but the extension of a lawful use to any portion of a nonconforming building which existed prior to the enactment of this chapter shall not be deemed the extension of such nonconforming use.

Unsafe structures. Any structure or portion thereof declared unsafe by a proper authority, but not ordered to be demolished, may be restored to a safe condition.

Those uses existing at the date of the adoption of this chapter which would otherwise be permitted only with a special use permit may be required to meet certain regulations as set forth in Article XII, Uses Requiring Special Use Permits, for the particular use.

A nonconforming building may not be reconstructed or structurally altered during its life to an extent exceeding in aggregate cost 50% of the true 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 nonconforming use may be changed to a use of the same classification upon approval of the Board of Appeals, or to a use of more restricted classification, and when so changed to a more restricted classification such use thereafter shall not be changed to a less restricted classification.

Normal maintenance repairs and structural alterations of building or other structure containing a nonconforming use shall be permitted, provided that it does not extend the area or volume of space occupied by the nonconforming use.

Amendments. Whenever the boundaries of a district shall be changed so as to transfer an area from one district to another district of a different classification, or whenever the text of this chapter shall be changed with respect to the uses permitted in a district, the foregoing provisions shall also apply to any nonconforming uses existing therein.

At any time after the effective date of this chapter, on the written request of the user of any structure or premises or at the instance of the Code and Zoning Enforcement Officer, an examination by the Code and Zoning Enforcement Officer of any existing use shall be made. A report of the findings made upon such examination shall thereafter be filed together with a certificate of noncompliance which shall clearly describe the premises and structure, if any, referred to and shall specify the nature and extent of the existing use. Such certification shall be prepared in duplicate, one copy of which shall be maintained by the Code and Zoning Enforcement Officer, and one copy of which shall be furnished to the owner or user.

Any building which is nonconforming due to insufficient yard distances or lot area shall not be considered a nonconforming use. Any alterations or structural changes may be accomplished within the existing frame of said building, but any additions shall conform to the specific setback and yard distance requirements of this chapter. The use of any such nonconforming building may be changed to any other permitted use so long as the yard or lot area requirements are not greater.

An existing house trailer may be located on the site where a building is to be erected, and for which a building permit has been issued, provided that such trailer is located no closer than five feet from any lot line. The trailer shall be removed from the premises not later than the date the building permit expires, or within 30 days after occupancy of the building, whichever is the prior date.