Any agent, owner or occupant of a business building in complying with the provisions of this subchapter may do the necessary work himself or may engage a contractor to do the work, or may have the work performed by the employment of such labor and the purchase of such materials as may be necessary in a manner and according to plans approved by the Health Officer. At the option of such agent, owner or occupant, however, he may make application to the Health Officer who will have the necessary ratproofing or the work of rat-elimination done at cost. The cost in each such case, whether for original ratproofing or elimination, or for renewals thereof, or for complying with the provisions of any notice shall be agreed upon by the agent, owner or occupant, as the case may be, and the Health Officer prior to the doing of the work, and the amount agreed upon shall be paid in advance in each case to the City Treasurer.
('70 Code, § 11-23)