Within the zoning districts established by this chapter, or amendments that may later be adopted, there shall 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 amendments.

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 zoning districts involved. It is further the intent of this chapter that nonconformities shall not be enlarged upon, expanded or extended if such a change increases the nonconformity or is used as grounds for adding other structures or uses prohibited elsewhere in the same zoning 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 zoning district involved. Nothing in this chapter shall be deemed to require a change in the plans if construction was lawfully begun prior to the effective date of adoption or amendment of this chapter.

In any zoning 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 of amendments of this chapter. This provision shall apply even though such lot fails to meet the requirements for area or lot frontage, or both, that are generally applicable in the zoning district, provided that yard dimensions and other requirements not involving area or frontage, or both, of the lot shall conform to the regulations for the zoning district in which such lot is located. Variance of yard requirements shall be obtained only through action of the ZBA.

Nothing in this chapter shall restrict the future construction of structures in conformance at the effective date of this chapter in subdivisions in the process of approval at such effective date or in subdivision approved prior to such effective date.

No such nonconforming use shall be enlarged or increased or extended to occupy a greater area of land than was occupied at the effective date of adoption or amendment of this chapter.

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 or amendment of this chapter.

If any such nonconforming use of land ceases to exist for a period of one year, any subsequent use of such land shall conform to the regulations specified by this chapter for the zoning district in which such land is located unless the owner demonstrates to the satisfaction of the ZEO that the owner's intent was not to abandon such use.

Should such structure be destroyed or damaged by fire, explosion or act of God it may be repaired or replaced to its original dimensions existing immediately prior to such damage or destruction. If such repair or replacement is not begun within one year from the date of such damage or 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 whatsoever, it shall be made to conform to the regulations for the zoning district in which it is located after it is moved.

Such nonconforming structures shall not be structurally altered, reconstructed or expanded unless such alterations or expansions conform to all applicable setback, building height, coverage and use requirements, or are alterations required by law. In addition, maintenance and repair work required to keep a nonconforming structure in sound condition shall also be permitted.

In accordance with the provisions of the Connecticut General Statutes § 8-13a, when a building is so situated on a lot that it violates this chapter with respect to its relation to the boundaries of the lot, and such building has been so situated for three years without the institution of an action by the administrative official to enforce such regulations, such building shall be deemed a nonconforming building in relation to such boundaries. Although the structure may become legally nonconforming with respect to its relationship to the boundaries of the lot, it shall not become legally nonconforming with respect to any other provisions of this chapter, uses of land, structures, or both, which were not legally established prior to this chapter or in conformance with this chapter, and shall not become legally nonconforming by the passage of time.

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

Any structure or structure and lot in combination, in or on which a nonconforming use is superseded by a permitted use, shall thereafter conform to the regulations for the zoning 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 lot in combination, ceases to exist for one year, the structure and premises in combination shall not thereafter be used except in conformance with the regulations of the zoning district in which it is located unless the owner demonstrates to the satisfaction of the ZEO that the owner's intent was not to abandon such a use.