Regulations, Reporting, and Public Health
What you must understand
Know the regulatory framework: the Safe Drinking Water Act, National Primary Drinking Water Regulations, Maximum Contaminant Levels (MCLs), Maximum Contaminant Level Goals (MCLGs), treatment techniques, and secondary standards. Understand the Total Coliform Rule / Revised Total Coliform Rule and site sampling, disinfection byproduct rules, Lead and Copper Rule, Surface Water Treatment Rule (including CT and turbidity limits), and Ground Water Rule. Know monitoring and reporting requirements, public notification tiers (immediate, 24-hour, 30-day, annual), and Consumer Confidence Reports.
Understand public health principles: the multiple-barrier approach, why indicator organisms (total coliform, E. coli) are monitored, and the role of sanitary surveys. Know recordkeeping and compliance consequences.
Traps
Frequent confusion: MCL (enforceable limit) vs. MCLG (health goal, often zero) and secondary (aesthetic) standards. Another trap: mixing public notification tiers and deadlines. Watch for questions on turbidity limits (commonly 0.3 NTU in 95% of samples for conventional filtration, never above 1 NTU) and on who must be notified and when.
Rule of thumb
When in doubt about a violation, the safe operational response is to notify the primacy agency promptly and follow the required public notice tier-late notice is itself a violation. Treat MCLG as the target and MCL as the legal line.