The entire expense of doing the work of filling in a lot, including the expense of advertising and the services of the city engineer, shall be assessed and apportioned against and upon such real estate ratably, and such apportionment shall be made by the city engineer as the work is completed, who shall make a list thereof, and file the same with the city clerk. If no objections are made to the assessment within five days after the same is so filed, the assessment shall become final and conclusive. If objections are made, the city council shall fix a day for hearing the same, and shall equalize the assessment so as to be fair and just. After the lapse of such five days, if no objections are made, or after the city council shall have passed upon them, if made, the assessment shall be final and conclusive, and shall be immediately due and payable, and shall constitute a lien upon the real estate, which lien shall relate to and take effect as of the date of the acceptance of the bid and approval of the bond of the bidder for doing the work. (Prior code § 21.04.025)