(1) If, within the ten days allowed by section 6.830 for abating a nuisance as defined in section 6.815, the nuisance has not been privately abated, the city manager or his designate shall cause it to be abated.

(2) The person authorized to cause, or retained to do, the abating may enter upon the property at reasonable times for purposes of investigating and abating the nuisance.

(3) The finance officer shall keep an accurate record of the expense incurred by the city in abating the obnoxious vegetation and shall include therein a reasonable charge for administrative overhead.

(4) Whenever the city abates obnoxious vegetation, in addition to any penalty judicially imposed and to the costs specified in subsection 6.835(3), there is hereby imposed on each parcel in separate ownership or contiguous parcels in single ownership, a penalty of $50 or ten percent (10%) of the abatement costs, whichever is greater. The finance officer shall add the penalty to the amount to be collected as provided in section 6.840. The finance officer shall waive the penalty if the abatement costs are paid within the time specified in subsection 6.840(3).