Section 16-345-5(i) of the Regulations of Connecticut State Agencies (RCSA) establishes a color code for marking underground utility facilities:

(1) Yellow:  Gas, oil petroleum products, steam, compressed air, compressed gases and all other hazardous materials except water;
(2) Red:  Electric power lines, electric power conduits and other electric power facilities;
(3) Orange:  Communication lines or cables, including but not limited to telephone, telegraph, fire signals, cable television, civil defense, data systems, electronic controls and other instrumentation;
(4) Blue:  Water;
(5) Green:  Storm and sanitary sewers and drainage systems including force mains and other non-hazardous materials;
(6) Purple:  Reclaimed water, irrigation and slurry lines;
(7) White:  Designated area of proposed excavation or demolition; and
(8) Pink:  Survey markings.

See Section 16-345-5 of the RCSA for complete details of surface marking requirements.