Sec. 6-17. Restraint of dogs.

(a) On premises of owner. No dog shall be left unattended outdoors unless it is restrained and restricted to the owner’s property by: a tether while in the presence of the owner or other competent person; above-ground fence; underground fence (a containment system for dogs which includes a border created by a buried wire, a transmitter and a receiver collar); or a secure enclosure.