A. After the warrant and assessment are recorded, they shall be delivered to the contractor, or to the treasurer of the municipality if the municipality charges itself with the duty of making demands for the payment of the several assessments, together with one of the diagrams, and by virtue of the warrant, the contractor or treasurer, as the case may be, is authorized to demand and receive the amount of the several assessments.

B. The contractor or treasurer, as the case may be, shall call upon the person assessed, either in person or by use of the United States mail if the person can conveniently be found, and demand payment, and if paid shall give a receipt therefor. The receipt, when presented to the superintendent, shall be an order to the superintendent to release the assessment.

C. The contractor or treasurer shall promptly notify the superintendent of all payments made to the contractor or treasurer, whereupon the superintendent shall release assessments which have been fully paid. When the name of the owner of the lot is stated as "unknown" on the assessment, the contractor or treasurer shall demand payment of a person in possession. If someone is in possession, such demand may be made either by use of the United States mail, if a mailing address for the person in possession can be determined, or in person. If the premises are unoccupied or the person in possession cannot be found, such demand is unnecessary.

D. The warrant shall be returned to the superintendent within thirty days after its date with a "return" endorsed thereon, signed by the contractor or treasurer, as the case may be, verified upon oath stating the nature and character of the demand, and whether any assessments remain unpaid in whole or in part, and the amount thereof. In the absence of fraud or bad faith, the verified statement of the person making the return is conclusive proof that the demand for payment was made upon each owner, person in possession or each parcel of property as required by this section. The superintendent shall record the return so made in the margin of the record of the warrant and assessment. After return of the assessment and warrant all amounts remaining due shall draw interest at the rate of eight per cent per annum until paid or, upon the issuance of bonds, at the rate specified in the bonds payable for the semiannual period specified in the bonds notwithstanding the fact that the installments of assessments may be due at dates earlier than installments of interest are payable on the bonds.

E. After completion of the work, the superintendent shall notify the governing body of such fact, and the board shall fix a time when it will hear and pass upon the assessment and the proceedings theretofore had and taken, which shall not be less than twenty days thereafter. The governing body shall cause notice of the hearing to be given by publication for five days in a daily newspaper published and circulated in the municipality, or two times in a semiweekly or weekly newspaper so published, and the street superintendent shall cause notices of the time and place of the hearing to be mailed by first class mail, at least twenty days before the hearing date, to all persons owning real property affected by the assessments as the names and addresses appear on the last certified property tax roll. If no address appears for any person on the last certified tax roll, then no notice need be mailed to such person. The street superintendent shall make an affidavit of the mailing and shall recite therein that the persons to whom notices were mailed constitute all persons whose names and addresses appear upon the tax roll as owning property within the particular improvement area, which affidavit shall be conclusive proof that notice was mailed each person to whom notice is required to be mailed. Failure to receive notice shall not constitute any jurisdictional defect invalidating any proceeding or assessment if notice has been sent pursuant to this section.

F. If the assessment is dated before the work has been completed, the superintendent shall file with the clerk, at or prior to the hearing, a recapitulated assessment based on the actual quantities determined by the engineer to have been constructed or installed, or the actual cost of the acquisition, as the case may be, together with the known incidental expenses expended to that date and the itemized estimated incidental expenses remaining to be expended. The engineer need not recompute each individual assessment but shall determine the amount of the increase or decrease to be assessed and shall file a supplemental statement with the clerk setting forth the ratio of the differential between the contractor’s bid and the recapitulated amount and ordering that each assessment be increased or decreased, as the case may be, by such ratio. If the total assessment is decreased, the treasurer shall return to the owner, if the owner can be located, that portion of each assessment previously paid in cash which represents an excess payment.

G. The owners, contractor and all other persons directly interested in the work or in the assessment, who have any objection to the legality of the assessment or to any of the previous proceedings connected therewith, or who claim that the work has not been performed according to the contract, may, prior to the time fixed for the hearing, file a written notice briefly specifying the grounds of their objections. At the time fixed for the hearing or at any time not later than ten days thereafter to which the hearing may be postponed, the governing body shall hear and pass upon the objections. The decision of the governing body shall be final and conclusive upon all persons entitled to object as to all errors, informalities and irregularities which the governing body might have remedied or avoided at any time during the progress of the proceedings.

H. If the governing body finds that the contract has not been fully performed, it shall withhold all amounts or bonds owed and not then paid, or delivered, to the contractor until such time as in its opinion the contract is fully performed. If the governing body finds that the amount or bonds left on hand to be paid to the contractor is not sufficient to pay the costs necessary to complete the work and that the contractor is not likely to complete the work according to the contract, the governing body may summon the contractor and contractor’s surety for a hearing pursuant to section 48-586. The governing body may modify the amounts of the several assessments after hearing, and may order that the assessment be recomputed if it finds that the benefits to any lots do not equal the amount of such lot’s respective assessment. When recomputing the assessment, the superintendent of streets shall again levy the assessments according to the benefits derived, as instructed by the governing body, notwithstanding the fact that the reduction of any assessment may cause a corresponding increase in other assessments.