Except as provided in §§ 130-71 and 130-72, any use of land, or a building or structure or part thereof, existing at the time that this chapter or any amendment hereto becomes effective, may be continued, subject to the provisions of §§ 130-73, 130-74, 130-75 and 130-76, although such building or structure or use does not conform to the provisions of the district in which it is situated.

When a nonconforming use has been discontinued for a period of not less than one year, it shall not be reestablished, and the future use shall be in conformity with the provisions of this chapter.

Notwithstanding any other provision of this chapter, any automobile or other salvage yard or any nonconforming billboard sign or advertising device in existence in a residential district at the time of the adoption of this chapter or amendment thereto shall be discontinued within three years from the date of such adoption or amendment.

No nonconforming use shall be changed to other than a conforming use for the district in which it is situated.

A nonconforming use is hereby required to be maintained in such a condition as will not constitute a danger to the safety or general welfare of the public.

Alterations, extensions and repair of the nonconforming use, in order to comply with the provisions of this article, are permitted, provided that such alterations, extensions and repairs shall not tend to increase the inherent nuisance, nor shall such alteration, extension and repair violate any provisions of this chapter regarding yards, lot area or lot coverage for the district in which it is situated, or to increase any existing violations of such provisions.

No nonconforming use of land shall be extended beyond the original boundaries of such nonconforming use existing at the time that this chapter or any amendment hereto becomes effective.

No building or structure designed for or intended to be utilized for a nonconforming use shall be constructed unless construction, reconstruction or alteration is already underway at the time the enactment or subsequent amendment of this chapter and is being diligently prosecuted so that such building or structure will be completed within 18 months from the time of the enactment or subsequent amendment of this chapter. All outstanding building permits for construction which do not meet these requirements shall be rendered null and void by the enactment or subsequent amendment of this chapter.

The above limitations shall not apply to a building or other structure utilized as a dwelling which is nonconforming only in respect to yard space or dwelling and nonconforming to the district in which located, except that no building shall be altered, added to or reconstructed to extend further into an already deficient yard space or to reduce an already deficient amount of land area per dwelling.

Temporary permits may be issued by the Zoning Enforcement Officer for a period not exceeding one year for nonconforming uses incident to housing and construction projects, including structures and uses as storage of building materials and machinery, the processing of building materials and a real estate office located on the tract being offered for sale, provided that such permits are conditioned upon agreement by the owner or operator to remove the structure or structures or use upon expiration of the permit. Such permits may be renewed upon application to the Zoning Enforcement Officer for additional six-month periods, provided that the Zoning Enforcement Officer determines that substantial progress is being made.