The lawful use of any structure or land existing at the time of the enactment of this chapter may be continued although such use does not conform to the provisions of this chapter.

Any building or structure for which a valid building permit was lawfully issued prior to the effective date of this chapter may be completed and used in accordance with the plans and specifications for such building or structure.

Any preexisting legal use which is allowable by special use permit under this chapter, but which has not been issued a special use permit, shall be considered a permitted use. The expansion of such a use, other than a single-family or two-family residence, shall require site plan approval, unless such expansion has been permitted by a prior site plan approval.

A nonconforming use of land or structure shall be maintained and shall not constitute a danger to the health, safety or general welfare of the public. Nothing in this article shall prevent the strengthening or restoring to a safe condition any wall, floor or roof which has been declared unsafe by the Zoning Enforcement Officer or the Building Inspector.

The nonconforming use of land or structure shall not be enlarged or extended beyond the area of land or structure occupied by such use on the effective date of this chapter.

A nonconforming use of land may not be moved in whole or in part to any other portion of the lot or parcel of land occupied by such nonconforming use on the effective date of this chapter.

A nonconforming use shall not be changed to another nonconforming use without approval by the Zoning Enforcement Officer and Corporation Counsel, and then only to a use which, in the opinion of said authorities, is more restricted and more compatible with the surrounding neighborhood in which it is located. A change of use and compliance certificate will be issued by the Zoning Enforcement Officer. No building or land changed to a more restricted nonconforming use shall be changed back to a less restrictive use.

If a nonconforming use is discontinued for a period of 12 consecutive months, it shall not be renewed, and any subsequent use of the land shall conform to the regulations of the district in which the premises is located. A use shall be deemed to have been discontinued under any of the following conditions:

If a structure devoted to a nonconforming use is destroyed or damaged by fire, wind, explosion or other natural causes, it may be rebuilt, restored or repaired.

If any structure in which any nonconforming use is conducted is hereafter removed for reasons or circumstances other than those described in Subsection F above, the subsequent use of the land on which such building was located and the subsequent use of any building erected thereon shall conform with the regulations of the district in which it is located.

A nonconforming structure shall be maintained and shall not constitute a danger to the health, safety or general welfare of the public.

Where there is a conforming use in a noncompliant building, nothing in this article shall be deemed to prevent the reconstruction or enlargement of a noncompliant building containing a conforming use, provided that such action does not create any new noncompliance or increase the degree of noncompliance with regard to the regulations pertaining to such buildings.

A residential lot in an R-1, R-2, R-3, MU-1 or MU-2 District existing on the effective date 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 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.

No lot in existence on the effective date of this Zoning Ordinance shall be subdivided or diminished in area in such a way that the lot area, frontage, width, front, side or rear yard, coverage, required parking spaces or green space no longer meets the requirements of these regulations or any permit issued thereunder.