Manufacturers and models of approved backflow prevention assemblies for each type of assembly, double check (DC) or Reduced Pressure (RP), are listed in the document “List of Approved Backflow Prevention Assemblies” distributed by Foundation for Cross-Connection and Hydraulic Research, University of Southern California.
Potable Water Service
An approved backflow prevention assembly must be installed on each potable water service connection to any premises containing specific types of facilities. Listed below are examples of facilities and the minimum protection required to be installed for each type of facility. This list represents the minimum requirements and should not be construed as a complete record of all facilities. The minimum approved backflow prevention assembly for unlisted facilities will be determined on a case-by-case basis by the Cross Connection Control Program.
| Type of Facility | Minimum Protection |
| Commercial | RP |
| Industrial | RP |
| Sewage Pumping Station (lift station) | RP |
| Multistory | RP |
| Multifamily Residential | determined by degree of hazard |
| Single-Family Residential | determined by degree of hazard |
In addition to the specific facilities listed above, an approved backflow prevention assembly must be installed on each potable water service connection to any premises containing an actual or potential hazard. Listed below are examples of hazards and the minimum protection required to be installed for each type of hazard. The minimum approved backflow prevention assembly for unlisted hazards will be determined on a case-by-case basis by the Cross Connection Control Program.
| Type of Hazard at Premises | Minimum Protection |
| Any type of well | RP |
| Flood hazard area (if only condition) | DC |
| Auxiliary water system not connected to public water system | RP |
| Cooling system using chemical water conditioner | RP |
| Fire Sprinkler System | RP |
| Fountain with dedicated fill pipe | RP |
| Hot water heating system using chemical water conditioner | RP |
| If cross connection is found | RP |
| Irrigation system | RP |
| Property abuts or includes body of water (i.e., river, bay, lake or pond) | RP |
| Reclaimed water (assembly at potable water meter) | RP |
| Self-draining yard hydrant, fountain, hose, box or similar assembly | RP |
| Solar water heating system | RP |
| Steam boiler using chemical water conditioner | RP |
| Swimming pool | RP |
| Water storage tank, reservoir, pond or similar appurtenance | RP |
Fire Protection Service
An approved backflow prevention assembly must be installed on each fire protection service to any premises where the fire protection system contains any of the components listed below, unless the Cross Connection Control Program determines that no actual or potential hazard to the public water system exists. Fire systems are divided into six (6) general classes. Listed below are descriptions of the classes and the minimum protection to be provided for each class.
| Class | Description | Minimum Protection |
| 1 | Closed automatic fire system with no pump connection (i.e., 20 heads or less) | None |
| 2 | Closed automatic fire system with pump connection | DC |
| 3 | Closed automatic fire system with pump connection and auxiliary water supply on or available to premises or located within 1,700 feet from pump connection | RP |
| 4 | Closed automatic fire system with closed pressure tank supply (jockey pump may be interconnected with domestic water supply and/or air compressor connection) | RP |
| 5 | Closed automatic sprinkler system interconnected with auxiliary water system | RP |
| 6 | Fire system used for combined purpose of supplying automatic sprinklers, hose lines, fire hydrants and standpipes and domestic water for industrial purposes: | RP |
| 6(A) | Self-draining fire hydrant on premises presenting health or system hazard (i.e., bulk storage yard, chemical plant, fuel storage plant, sewage treatment plant, stockyard or similar facility) | RP |
| 6 (B) | Self-draining fire hydrant on premises presenting pollution hazard (i.e., multi-family residential building, fabrication plant, office building or similar facility | DC |
