§ 4  CROSS-CONNECTION PROHIBITED.
   (A)   Connections between potable water systems and other systems or equipment containing water or other substances of unknown or questionable quality are prohibited except when and where approved cross-connection control devices or methods are installed, tested and maintained to insure proper operation on a continuing basis.
   (B)   No physical connection shall be permitted between the potable portion of a supply and any other water supply not of equal or better bacteriological and chemical quality as determined by inspection and analysis by the Agency.
   (C)   There shall be no arrangement or connection by which an unsafe substance may enter a supply.