Whenever any sidewalk has been ordered built, repaired, relaid or replaced, the dirt removed therefrom may be used by the city for improving the street upon which the building or repairs are being made or on streets, alleys or public places the grading of which is of the same general plan.  In case the city does not so use the dirt, the property owner may remove it together with all old material within five days from the completion of such work.  In case the property owner fails to do so, the contractor shall proceed to remove the same and the cost thereof shall be collected as part of the cost of such improvement.  It shall be the duty of the contractor at all times while building, repairing, relaying or replacing any sidewalk to see that the stakes indicating the grade thereof have not been tampered with.
(`94 Code, § 95.19) Penalty, see § 10.99