Which factor most directly influences the risk of cross-connections in a building?

• A. Proximity to non-potable water sources
• B. The color of interior finishes
• C. The season of the year
• D. The number of people in the building

Answer: (A)

Proximity to non-potable water sources is the main factor because cross-connections occur when the potable drinking-water system could come into contact with non-potable sources. The closer those non-potable sources are to the potable lines, the greater the chance that a backflow path could form or be created through improper piping, shared components, or a failed backflow prevention device. In other words, the physical closeness of non-potable systems directly raises the risk of contamination entering the drinking water.

The other factors don’t directly affect the possibility of a cross-connection. The color of interior finishes has no bearing on how pipes or connections are laid out. The season might influence irrigation use, but it doesn’t change the plumbing configuration or the potential for backflow. The number of people in the building affects water demand and pressure, which can influence backflow if protection isn’t adequate, but it’s not the direct cause of a cross-connection itself.