Sec. 9. (a) If a landowner in the proposed district is not a resident of one (1) of the counties in which the proposed district will lie, the petitioners shall file in the clerk's office with the petition an affidavit that does the following:
(1) Gives the name of every nonresident landowner.
(2) States the landowner's post office address if known.
(3) If the landowner's post office address is not known, states that diligent inquiry has been made to ascertain the address but has not been able to do so.
(b) The clerk shall mail a copy of the notice to every nonresident landowner whose post office address is stated in the affidavit not later than the day on which publication of the notice is made.