What is an operator's primary defense against back flow from cross connections?

• A. Installing backflow preventers
• B. Maintaining adequate system pressure
• C. Regular flushing
• D. Monitoring flow rates

Answer: (B)

Maintaining adequate system pressure is the main defense because backflow from cross connections happens when pressure in the distribution system drops below the pressure on the other side of a connection, or when a negative pressure is created that can pull water backward. If the system keeps pressure consistently high and resilient, water continues to flow forward rather than back toward the source, preventing reverse flow and potential contamination.

Backflow preventers at the cross-connection are important safety devices, providing a physical barrier if pressure conditions somehow permit reverse flow, but they depend on proper design, installation, and maintenance and aren’t as universally protective as keeping the entire system pressurized. Regular flushing and monitoring have valuable roles for water quality and system operation, but they don’t by themselves prevent backflow.