Which combination of facilities is listed as requiring the highest level of cross-connection and backflow protection?

• A. Sewage plant and agricultural pesticide mixing tanks, hospitals and funeral homes
• B. Residential homes and schools
• C. Office buildings and parks
• D. Industrial factories

Answer: (A)

Cross-connection control targets preventing backflow from non-potable sources into the drinking water, and the level of protection scales with how hazardous the potential backflow could be. The combination that includes a sewage plant, agricultural pesticide mixing tanks, hospitals, and funeral homes presents the highest health and safety risk: raw sewage carries dangerous pathogens; pesticide mixing introduces highly toxic chemicals; hospitals and funeral homes handle hazardous materials and care workflows that can generate contaminated water sources. When any of these could backflow into the potable system, the risk to public health is greatest, so the strongest protection is required, typically the most stringent backflow prevention measures allowed (such as RPZ assemblies or equivalent protections). Other options involve lower or more routine hazards, which require less stringent protection.