Which statement about cross-connections and backflow risk is correct?

• A. A cross-connection is any physical link between potable water and a non-potable source that could contaminate supply.
• B. A cross-connection only refers to electrical grounds.
• C. Cross-connections are acceptable if a guard valve is present.
• D. Cross-connections are allowed in unprotected areas.

Answer: (A)

Cross-connections create backflow risk because they provide a physical link between potable water and a non-potable source, which could allow contaminants to be drawn into the drinking-water supply if pressure conditions reverse. This is the core idea: any connection that could contaminate the supply is a cross-connection, and it must be prevented or protected with proper backflow devices. The other statements miss the hydraulics focus—cross-connections are not about electrical grounds. Simply having a guard valve does not make a cross-connection acceptable, since backflow can still occur if the protection isn’t adequate. And cross-connections aren’t allowed in unprotected areas; protection is required to prevent contamination.