Rules, Regulations, and Administration
Where the rules come from
The Clean Water Act sets the framework, and EPA delegates permitting to states with primacy. A facility's NPDES permit lists effluent limits (monthly average, weekly average, daily maximum), monitoring requirements, and reporting duties. Limits and sampling methods are enforceable - a sample collected the wrong way is a violation even if the water was clean.
Reporting clocks
Discharge Monitoring Reports (DMRs) are signed by a responsible official and submitted within 28 days after the end of each monitoring period (a monthly report is due by the 28th of the following month). Supporting records are kept at least three years. Noncompliance that may endanger health or the environment requires a telephone or electronic report within 24 hours, followed by a written submission. Bypass: oral notice within 24 hours, written within 5 days. Upset: oral within 24 hours, written within 5 days - and the upset defense only applies if the plant was operated properly and notification was timely.
Other programs
Sanitary sewer overflows are reported to the state and the public, often within 24 hours. Industrial users are controlled through the pretreatment program. Biosolids land application follows 40 CFR Part 503 (pathogen reduction, vector attraction reduction, site limits). Operator certification, continuing education, and staffing come from the state. Spill prevention (SPCC) and chemical inventory reporting may also apply.
Traps
Questions swap upset and bypass, or misstate the DMR clock. Memorize: 24-hour oral, 5-day written, 28-day DMR.
Worked example
A permit limits ammonia to 8 mg/L as a monthly average. Weekly results of 6, 9, 11, and 7 mg/L average 8.25 mg/L - an exceedance even though three samples were below the limit. Monthly averages, not single samples, are compared to monthly average limits.