Within the zoning districts established by this chapter, there exist uses and lots of land that were lawful before this chapter's adoption but which are now prohibited, regulated or restricted under the terms of this chapter. 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 considered incompatible with the permitted uses in the zoning districts involved.

A nonconforming structure may be modified, expanded and/or enlarged, so long as:

A nonconforming use may be extended throughout a building that was designed and arranged specifically for the nonconforming use, but the nonconforming use shall not be permitted to occupy land outside the building. If the use of any such nonconforming structure or lot ceases for any reason for a period of more than 12 consecutive months, any subsequent use of the structure or lot shall conform to the regulations specified by this chapter for the zoning district involved.

In any zoning district in which single-family residential buildings are permitted, a single-family residential building and associated accessory buildings may be erected on any single lot of record existing on the date of adoption or amendment of this chapter. Such a lot must be in separate ownership and not of continuous frontage with other lots in the same ownership. This provision shall apply even though the lot fails to meet the zoning district's requirements for area or width, or both, provided that the lot conforms to the zoning district's setback dimensions and other requirements not involving area or width, or both. Variance of area, width and setback requirements shall be obtained only through action of the Zoning Hearing Board.

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 article, and if all or part of the lots do not meet the requirements for lot width and area as established by this article, the lands involved shall be considered to be an undivided parcel for the purposes of this article, and no portion of the parcel shall be used or sold which does not meet lot width and area requirements established by this article, nor shall any division of the parcel be made which leaves remaining any lot with width or area below the requirements stated in this article.