Del. Code tit. 22, § 1102

The election by the municipality to use the county assessments shall be made before February 1 of any year and shall continue in effect from year to year until revoked by ordinance adopted by the municipality. Notice of such election shall be given to the board of assessment or board of assessment review prior to March 1 in the year in which such election occurs and shall be published at least once a week for 2 weeks prior to March 1 of each year in at least 2 newspapers in the municipality, or to the extent no such newspaper exists, then in a newspaper of general circulation in the county in which such municipality is located.