Regulations, Records, and Reporting
Know the rule, the number, and the clock
Regulatory questions usually hinge on one acronym and one deadline. Build a framework: the Safe Drinking Water Act authorizes EPA's National Primary Drinking Water Regulations (health-based: MCL, treatment technique, MRDL) and Secondary standards (aesthetic: iron, manganese, sulfate, chloride). Distinguish an MCL (measured at the tap, enforceable) from a treatment technique (a required process used when monitoring is impractical - turbidity, LT2, lead and copper), and remember the MCLG is a non-enforceable health goal.
Place the rules: Stage 1/2 Disinfectants and Disinfection Byproducts Rule (TTHM 80, HAA5 60 µg/L as LRAA) with enhanced coagulation; LT1/LT2 ESWTR; the Ground Water Rule (4-log virus treatment); the Revised Total Coliform Rule (routine monitoring, assessment triggers, Level 1 and Level 2 assessments, E. coli as the acute indicator); the Lead and Copper Rule; the Consumer Confidence Report due by July 1 annually; and Public Notification tiers - Tier 1 within 24 hours, Tier 2 within 30 days, Tier 3 within a year. Sanitary surveys are routine (surface water generally at least every 3 years), and states act as primacy agencies and may be stricter.
Records to keep and produce: monitoring results, DMRs, calibration and maintenance logs, chain-of-custody forms, public notices, and current operator certification.
Rule of thumb: study every rule as who monitors → what number → how often → what happens on a failure.
Traps: quoting an MCLG as enforceable; applying a running annual average where a single sample governs; missing the notification clock.