N.J. Stat. § 40:56-24
Upon the completion of any local improvement the body in charge thereof shall immediately notify the officer, board or commissioners whose duty it is to make the assessment for benefits therefor, and shall certify to such officer, board or commissioners a statement showing in detail the cost of the improvement, including therein the cost of advertising, financing and inspection and the engineering expense, and also the cost of any real estate or interest therein purchased or condemned for such improvement. Such statement shall also show the proportion or amount of the whole cost of the improvement if any paid or contributed by the municipality, or by the board of chosen freeholders of the county in which the municipality is situated, or by any person. The total amount of the assessment levied upon the real estate benefited by the improvement shall not exceed the cost thereof, less any such payment or contribution. If the benefits so assessed shall not equal the cost less such contribution the balance shall be paid by the municipality.
N.J.S. § 40:56-24