Final answer:
A licensed plumber must have a backflow endorsement to perform a Cross-Connection Control Inspection (CSI), which is vital for protecting the potable water supply from contamination.
So option (C) is correct.
Step-by-step explanation:
The only way a licensed plumber can perform a CSI (cross-connection control inspection) is if they have a backflow endorsement on their license. Licensed plumbers must have this specific endorsement to legally inspect, test, maintain, and repair backflow prevention assemblies. This endorsement ensures that the plumber has the required knowledge and skills to prevent contaminated water from reversing flow and entering the clean water supply.
Backflow prevention is critical in plumbing to prevent the contamination of the public water supply. Plumbers with a backflow endorsement are equipped to install, test, and maintain backflow prevention devices, ensuring that water flows in one direction and doesn't allow contaminants to enter the clean water supply.
Having a backflow endorsement demonstrates a plumber's expertise in cross-connection control, making them eligible and authorized to perform CSIs as part of their commitment to maintaining water quality and safety in plumbing systems. It's an essential qualification to address the specific challenges associated with preventing backflow in plumbing installations.