(a) Any physical connection is prohibited whereby a public water system whether community or noncommunity, is connected to an unsafe or questionable water supply system either inside or outside of any building or buildings.
(b) Prohibited services.
(1) Domestic water shall not be supplied to any device, equipment, or service connection which may permit the contamination of the water supply by backsiphonage or backflow.
(2) Provision of water service to any service connection found to contain a cross-connection shall immediately be terminated, unless a backflow prevention device of a type approved by the Department of Health is installed between the cross-connection and the public water system.