Within the districts established by this chapter or amendments that may later be adopted, there exist lots, structures and uses of land and structures which were lawful before this chapter was passed or amended but which would be prohibited, regulated or restricted under the terms of this chapter or future amendment.

It is the intent of this chapter to permit these nonconformities to continue until they are removed, but not to encourage their survival. Such uses are declared by this chapter to be incompatible with permitted uses in the districts involved. It is further the intent of this chapter that nonconformities shall not be enlarged upon, expanded or extended, nor be used as grounds for adding other structures or uses prohibited elsewhere in the same district.

A nonconforming use of a structure, a nonconforming use of land, or a nonconforming use of a structure and land shall not be extended or enlarged after passage of this chapter by attachment on a building or premises of additional signs intended to be seen from off the premises, or by the addition of other uses of a nature which would be prohibited generally in the district involved.

To avoid undue hardship, nothing in this chapter shall be deemed to require a change in the plans, construction or designated use of any building on which actual construction was lawfully begun prior to the effective date of adoption or amendment of this chapter and upon which actual building construction has been diligently carried on. Actual construction is hereby defined to include the placing of construction materials in permanent position and fastened in a permanent manner; except that where demolition or removal of an existing building has been substantially begun preparatory to rebuilding, such demolition or removal shall be deemed to be actual construction, provided that work shall be diligently carried on until completion of the building involved.

In any district in which single-family dwellings are permitted, notwithstanding limitations imposed by other provisions of this chapter, a single-family dwelling and customary accessory buildings may be erected on any single lot of record at the effective date of adoption or amendment of this chapter. Such lot must be in separate ownership and not of continuous frontage with other lots of the same ownership. This provision shall apply even though such lot fails to meet the requirements for area or width, or both, that are generally applicable in the district, provided that yard dimensions and other requirements not involving area or width, or both, of the lot shall conform to the regulations for the district in which such lot is located.

If two or more lots or combinations of lots and portions of lots with continuous frontage in single ownership are of record at the time of passage or amendment of this chapter, and if all or part of the lots do not meet the requirements for lot width and area as established by this chapter, the lands involved shall be considered to be an undivided parcel for the purposes of this chapter, and no portion of said parcel shall be used or sold which does not meet lot width and area requirements established by this chapter, nor shall any division of the parcel be made which leaves remaining any lot with width or area below the requirements stated in this chapter.

No such nonconforming use shall be enlarged or increased, nor extended to occupy a greater area of land than was occupied at the effective date of adoption.

No such nonconforming use shall be moved in whole or in part to any other portion of the lot or parcel occupied by such use at the effective date of adoption of this chapter.

If any such nonconforming use of land ceases for any reasons for a period of more than 12 months, any subsequent use of such land shall conform to the regulations specified by this chapter for the district in which such land is located.

No such structure may be enlarged or altered in any way which increases its nonconformity.

Should such structure be destroyed by any means to an extent of more than 75% of its replacement cost at time of destruction, it shall not be reconstructed except in conformity with the provisions of this chapter.

Should such structure be moved for any reason for any distance whatever, it shall thereafter conform to the regulations for the district in which it is located after it is moved.

No existing structure devoted to a use not permitted by this chapter in the district in which it is located shall be enlarged, extended, constructed, reconstructed, moved or structurally altered except in changing the use of the structure to a use permitted in the district in which it is located.

Any nonconforming use may be extended throughout any parts of a building which were manifestly arranged or designated for such use at the time of adoption of this chapter, but no such use shall be extended to occupy any land outside such building.

If no structural alterations are made, any nonconforming use of a structure, or structure and premises, may be changed to another nonconforming use, provided that the Board of Adjustment, either by general rule or by making findings in the specific case, shall find that the proposed use is equally appropriate or more appropriate to the district than the existing nonconforming use. In permitting such change, the Board of Adjustment may require appropriate conditions and safeguards in accord with the provisions of this chapter.

Any structure, or structure and land in combination, in or on which a nonconforming use is superseded by a permitted use, shall thereafter conform to the regulations for the district in which such structure is located, and the nonconforming use may not thereafter be resumed.

When a nonconforming use of a structure, or structure and premises in combination, is discontinued or abandoned for 12 consecutive months or for 24 months during any three-year period, the structure, or structure and premises in combination, shall not thereafter be used except in conformance with the regulations of the district in which it is located.

Where nonconforming use status applies to a structure and premises in combination, removal or destruction of the structure shall eliminate the nonconforming status of the land.

On any building devoted in whole or in part to any nonconforming use, work may be done in any period of 12 consecutive months on ordinary repairs or on repair or replacement of nonbearing walls, fixtures, wiring or plumbing, provided that the cubic content of the building as it existed at the time of passage or amendment of this chapter shall not be increased.

Nothing in this chapter shall be deemed to prevent the strengthening or restoring to a safe condition of any building or part thereof declared to be unsafe by any official charged with protecting the public safety, upon order of such official.