Which list identifies contaminants not regulated by current standards and monitored for potential future regulation?

• A. Contaminant Candidate List
• B. Unregulated Contaminant Monitoring Regulation
• C. National Secondary Drinking Water Regulations
• D. Total Coliform Rule

Answer: (A)

Identifying contaminants not yet regulated but potentially headed for future regulation. The Contaminant Candidate List is exactly that—the list EPA uses to flag unregulated contaminants that may need more research and monitoring to determine if they should become regulated in the future. It helps prioritize which substances to study and monitor so informed decisions can be made about adding them to enforceable standards.

The other options serve different roles. The Unregulated Contaminant Monitoring Regulation requires utilities to monitor certain unregulated contaminants to collect data, but it doesn’t identify which contaminants might be regulated later. National Primary Drinking Water Regulations are the actual enforceable limits for contaminants currently regulated. The Total Coliform Rule governs a specific regulated microbial contaminant, not a list of future candidates.