The owner of a multiple dwelling unit shall have the duty to exterminate therein for rodents and insects when infestation exists in two or more units or when infestation exists in shared or public areas of a multiple unit structure when the infestation is due to failure by the owner to maintain the dwelling in an insect and rodent proof condition. The owner of a single dwelling unit shall have the duty to exterminate therein notwithstanding the occupancy of a renter or lessee when the infestation of insects or rodents is due to the said owner's failure to construct or maintain the premises in such a manner as to make it reasonably resistant to the entrance and habitability of such pests.
('72 Code, § 4-503)