What is the effect of cross-connections at fixture connections on backflow risk?

• A. They help with mixing hot and cold water.
• B. They improve filtration.
• C. They create potential pathways for backflow into potable water if pressure changes, thus must be avoided.
• D. They have no effect on safety.

Answer: (C)

Cross-connections at fixture connections create a potential pathway for backflow into potable water if pressure changes occur. When the supply pressure drops or the pressure on a non-potable part of the system rises, water can be siphoned or pushed back into the clean water supply through that connection, risking contamination. That’s why such connections must be avoided or protected with backflow prevention devices or air gaps. The other choices miss the safety concern: mixing hot and cold water isn’t the issue here, filtration isn’t about backflow, and saying there’s no safety impact ignores the contamination risk.