The following list of hazard sources is arranged alphabetically. The "Hazard Level" for each source is listed as either "HI" or "LO" (high or low), while the "Test Cycle" indicated is the maximum duration in months allowed between device testing.

In accordance with section 290.47(i) Appendix I of Title 30 of the Texas Administrative Code, a "Health" hazard shall be considered a "HI" hazard while a "Nonhealth" hazard shall be considered a "LO" hazard. Refer to Table 603.2 "Backflow Prevention Devices, Assemblies and Methods" from the current adopted city plumbing code to determine which type of protection is suitable for the hazard level indicated. Refer to the Approved Backflow Prevention Assembly List for information on the specifically approved models.