Aircraft Plants
Automotive Plants
Autopsy Facilities
Auxiliary Water Systems
Beverage Bottling Plants
Boilers (large) or Hot Water Systems
Breweries
Buildings – Hotels, Apartments or other structures with unprotected cross-connections.  Multi-Storied Buildings.
Canneries
Car Wash Facilities
Chemical Plants Using Water Process
Chemical Manufacturing Plants
Clinics
Colleges
Commercial Laundries
Convalescent Homes
Dairies
Dental Buildings
Dye Works
Fabricating Plants
Film Laboratories
Food Processing Plant
Irrigation/Sprinkler System on Premises
Hospitals
Laboratories
Laundries
Manufacturing Plants
Medical Buildings
Metal Plating, Manufacturing & Processing Industries
Marinas
Missile Plants
Morgues
Mortuaries
Nursing Homes
Oil & Gas Production Facilities
Packing Houses
Paper & Paper Products Plants
Petroleum Storage Plants
Power Plants
Radioactive Materials or Substances Plants or Facilities
Reclaimed Wastewater Areas
Recreational Facilities Using Water (Swimming Pools)
Restricted, Classified or other Closed Facilities
Rubber Plants
Sand & Gravel Plants
Schools
Tanneries
Waterfront Facilities & Industries
Wastewater Treatment Facilities

Sources:

1. Manual of Cross-Connection Control, (9th Edition), 1993, Foundation for Cross-Connection Control and Hydraulic Research, University of Southern California.
2. Backflow Prevention Theory and Practice, (2nd Edition), 2004, University of Florida, TREEO Center.
3. Recommended Practice for Backflow Prevention and Cross-Connection Control, (3rd Edition), 2004 ,M-14 Manual,  American Water Works Association (AWWA).