What Is the USC Foundation for Cross-Connection Control?
What Is the USC Foundation for Cross-Connection Control and Hydraulic Research?
If you've ever received a backflow testing notice from your water utility or hired a certified tester to inspect your property, you've benefited from decades of work by an organization you've probably never heard of: the USC Foundation for Cross-Connection Control and Hydraulic Research. Based at the University of Southern California in Los Angeles, this foundation operates as the country's leading technical authority on cross-connection control and backflow prevention—shaping the standards that protect drinking water across the United States.
Close-up photograph of a certified backflow preventer assembly mounted on copper pipes outside a commercial property, showing pressure gauges and relief valve in detail
A Research Institution With National Reach
The USC Foundation was established in 1944, making it one of the oldest dedicated research programs in the field of water system safety. Its original mission was to study the hydraulics of cross-connections—points in a plumbing system where potable water could come into contact with non-potable water or contaminants. That mission has expanded considerably over the decades, but the core focus remains unchanged: ensuring that what comes out of your tap is as clean as when it entered your property.
The foundation operates out of the USC Viterbi School of Engineering and is funded through a combination of university support, water utility partnerships, and product evaluation fees. It functions as a technical standards body, not a regulatory agency. It cannot fine you or require you to test your backflow preventers. However, its work underpins nearly every backflow testing program in the country, which means its influence reaches into your compliance obligations whether you realize it or not.
The Manual of Cross-Connection Control
The foundation's most important publication is the Manual of Cross-Connection Control, currently in its tenth edition. This document is the closest thing the backflow prevention industry has to a master rulebook. It defines hazard classifications for cross-connections, specifies which type of backflow preventer is appropriate for which situation, and lays out the procedures that certified testers must follow when evaluating equipment in the field.
Many state plumbing codes and water utility programs reference or directly adopt sections of this manual. When your water utility requires a reduced pressure zone (RPZ) assembly rather than a simpler double check valve, the hazard classification system behind that decision almost certainly traces back to USC's framework. Property owners and facility managers who want to understand the reasoning behind their compliance requirements will find this manual to be the definitive source—and some utilities make it available on their websites for exactly that reason.
The USC Approved Backflow Prevention Assembly List
One of the most practically significant outputs of the USC Foundation is its list of approved backflow prevention assemblies. Before a backflow preventer can be legally installed under most water utility programs in the U.S., it typically needs to appear on an approved products list. The USC Foundation's list is one of the most widely recognized nationally, alongside lists maintained by the American Society of Sanitary Engineering (ASSE) and other bodies.
To appear on the USC approved list, a manufacturer must submit their assembly for rigorous hydraulic testing at the USC laboratory. Engineers test the device under a range of pressure conditions, flow rates, and failure scenarios to verify it performs as claimed. Assemblies that pass are added to the list; those that fail or later develop performance issues can be removed.
Plumbing engineer reviewing cross-connection control documentation and approved backflow assembly specifications on a desk in an industrial facility office
For property owners, this matters because your water utility will usually only accept assemblies from an approved list when you install or replace a backflow preventer. Installing an off-list device—even one that looks identical to an approved model—can result in a failed compliance inspection. When you or your contractor selects replacement equipment, verifying approval status before purchase saves significant time and expense.
Tester Certification and Training Programs
Beyond standards and product evaluation, the USC Foundation has played a foundational role in the certification of backflow prevention testers. The foundation developed early competency frameworks defining what a qualified tester needs to know: hydraulic principles, assembly mechanics, test procedures, and reporting requirements.
While tester certification today is administered through a network of state-approved programs, many of those programs were built on USC's curriculum. The testers who inspect your property have typically passed exams and field evaluations that trace their structure back to USC's work. This matters when evaluating a tester's credentials: a tester certified through a program that follows USC-aligned standards has demonstrated technical competency beyond simply knowing how to operate a gauge kit.
Why This Matters for Your Compliance Program
Understanding the USC Foundation's role helps property owners and facility managers navigate compliance more confidently. Here is how that knowledge applies in practice:
Assembly selection: When purchasing replacement backflow preventers, check the USC approved list before specifying equipment. Your utility may also maintain its own list, but the USC list is a reliable national baseline.
Hazard classification disputes: If your utility has classified your connection at a higher hazard level than you expected—requiring a more expensive assembly type—the USC manual's hazard definitions can help you understand the reasoning and, if appropriate, support a formal reassessment request.
Tester vetting: When hiring a backflow tester, asking about their certification program provides insight into their training depth. Programs that reference USC standards typically produce more technically grounded testers.
Staying current: The USC Foundation periodically updates its manual and approved list. Assembly models that were approved years ago can be delisted if performance problems emerge. Monitoring these updates helps you avoid compliance surprises during your next inspection.
Backflow prevention test kit with gauges and hoses laid out on a workbench beside a printed compliance test report form and clipboard
The Bigger Picture
No single organization can fully guarantee safe drinking water—that requires utilities, regulators, plumbers, property owners, and testers all doing their part. But the USC Foundation for Cross-Connection Control and Hydraulic Research provides the technical backbone that makes consistent, reliable backflow prevention possible across a country with thousands of different water systems. When your utility sends you a compliance notice and a certified tester shows up with a calibrated gauge kit, the protocols they follow connect back to research and standards that USC has refined over eight decades.
Understanding that foundation helps you be a more informed property owner—one who can ask better questions, make smarter equipment decisions, and recognize legitimate compliance requirements when they arrive.
Sources
U.S. Environmental Protection Agency — Cross-Connection Control Manual (EPA 816-R-03-002). Office of Water, 2003. Provides federal guidance on cross-connection hazards, program design, and the role of technical standards organizations in supporting utility compliance programs.
American Water Works Association (AWWA) — M14: Recommended Practice for Backflow Prevention and Cross-Connection Control, Fourth Edition. AWWA, 2015. Industry-standard reference for utility program managers that extensively cites USC Foundation standards and approved assembly criteria.
California State Water Resources Control Board — Title 17, California Code of Regulations, Sections 7583–7605: Cross-Connection Control. California's cross-connection regulations are among the most comprehensive in the nation and explicitly reference USC Foundation standards and the USC approved assembly list as the technical basis for statewide requirements.