USC Foundation
List of Approved Backflow Prevention Assemblies
Updated 10/1/2024
Shutoff Valve Designation
The backflow prevention assemblies shown on this list have been evaluated with a
specific set of shutoff valves as an integral part of the assembly. The specific
shutoff valves are coded by a parenthetic code shown with each assembly. This coding
of shutoff valves is defined below. Other shutoff valves having similar performance
characteristics which permit the assembly to comply with the standards are also
shown immediately after the original shutoff valves. The use of any shutoff valve
on a specific assembly, other than those listed for that specific assembly invalidates
the Approval. Assemblies listed with a Y in the “spare parts only" column may not
include the shutoff valve designation.