Approved Backflow Prevention Devices List
Those seeking to acquire the list of approved backflow prevention devices should call the Drinking Water Program at (916) 449-5600 and request a copy of the list [or the portion needed -- the list is by size of device, so if you’re only looking for a 4-inch reduced pressure (RP) backflow prevention device, for example, only a page or two may be needed].

• The list will only be provided via fax or US mail (no electronic copies will be provided).
• Copies will be provided only to regulated entities and consultants working in California.
• There is a limit of one per customer.

University of Southern California List of Approved Backflow Devices
(In order to view the approved list, a membership is required and explained on the USC's web site)