Delaware Code
Subchapter I. General Provisions
§ 4920. Nonconforming uses of land or buildings.

(a) The lawful use of a building or structure, or the lawful use of any land, as existing and lawful at the time of the enactment of a zoning regulation, or in the case of a change of regulations, then at the time of such change, may, except as hereinafter provided, be continued although such use does not conform with the provisions of such regulations or change, and such use may be extended throughout the same building, provided no structural alteration of such building is proposed or made for the purpose of such extension. The county government in any zoning regulations may permit the restoration, reconstruction, extension or substitution of nonconforming uses upon such terms and conditions as may be set forth in the zoning regulations.
(b) If the County acquires title to any property by reason of tax delinquency and such properties are not redeemed as provided by law, the future use of such property shall be in conformity with the then existing provisions of the zoning regulations of the County, or with any change of such regulations, equally applicable to other like properties within the district in which the property acquired by the County is located.

Structure Delaware Code