(A) Upon a determination that conditions described in this subchapter constituting a public nuisance exist, the Planning Director shall notify, in writing, the owner, occupant or person in possession of the premises in question of the conditions constituting such public nuisance and shall order the prompt abatement thereof within five calendar days from the receipt of such written notice.
(B) Notices and orders issued pursuant to this section shall be served upon persons either personally or by registered or certified mail and, in conjunction therewith, may be served by regular mail. When the manner of service is by regular mail in conjunction with registered or certified mail and the registered or certified mail is unclaimed or refused, but the regular mail is not returned by the post office within ten days after mailing, service shall be deemed sufficient. The person mailing the notice or order by regular mail shall certify that fact and the date thereof, and such certificate shall be conclusive in the absence of fraud. If the whereabouts of the person to receive the notice is unknown and the same cannot be ascertained in the exercise of reasonable diligence and an affidavit to that effect is made by the person attempting service, then the serving of such notice may be made by posting the notice on the subject property.