The potential hazard for this cross connection system is high.

• A. Pumps
• B. Boilers
• C. Valves
• D. Water Heaters

Answer: (B)

In cross-connection control, the level of hazard is determined by what could backflow into the potable water. A system that is classified as high hazard means backflow could introduce substances that pose a serious health risk. Boilers fit this because they’re often treated with chemical additives such as corrosion inhibitors, anti-scaling agents, and sometimes antifreeze. If backflow occurs, those chemicals can contaminate the drinking water and potentially cause toxic effects, which is why the hazard is considered high. The other items—pumps and valves—are mechanical components and don’t inherently contain or introduce hazardous substances into the water. Water heaters primarily carry potable water for domestic use and don’t typically involve toxic additives, so they don’t elevate the health hazard in the same way.