What is cross-connection control, and which are two plausible cross-connections in a domestic cold water system?

• A. A physical link between potable water and a non-potable source that could contaminate supply; examples include a garden hose on a lawn irrigation line and a laundry trough with a potential chemical feed line.
• B. A filter to remove cross-sectional debris; examples: strainer at faucet and screen in pipe.
• C. An electrical grounding path; examples: water meter ground and metallic pipe.
• D. A backflow valve; examples: check valve in main and pressure reducing valve.

Answer: (A)

Cross-connection control focuses on preventing backflow of contaminants into the potable supply by identifying and guarding any physical link between clean water and a non-potable source. In a domestic cold-water system, two plausible cross-connections are a garden hose attached to a lawn irrigation line and a laundry trough that has a chemical feed line connected to the water supply. If the system pressure drops or a backpressure condition occurs, these links can allow non-potable water or chemicals to be drawn back into the potable supply, risking contamination.

The other options describe things that don’t embody a cross-connection themselves. A filter is a treatment device, not a path for contaminants to flow back into the supply. Electrical grounding is unrelated to water contamination. A backflow valve is a device used to prevent backflow, not a cross-connection path itself.