Stormwater Sampling Requirements by State and Sector
This guide summarizes sampling analyte requirements under current and proposed stormwater permits for Indiana and surrounding states plus Texas. Click each card to explore general requirements and sector-specific benchmarks.
- Rule 6 Permit: 327 IAC 15-6 (Rule 6)
- Rule 6 Frequency: Annual grab sample (≥0.1" storm, ≥72 hr dry period)
- Rule 6 Analytes: pH (field), TSS, Oil & Grease, COD or CBOD, TKN, Total Phosphorus, Nitrate + Nitrite-N
- Draft ISGP General: Quarterly sampling (Year 1 and 4); pH, TSS, Oil & Grease
- Draft ISGP Sector J: pH, TSS, Oil & Grease, Nitrate + Nitrite-N (0.68 mg/L), Zinc, Lead
- General Industrial Stormwater Permit: OHR000006
- Frequency: Quarterly during year 1 of permit cycle
- General Analytes: pH, TSS, COD, Oil & Grease
- Sector J (Sand & Gravel): pH, TSS, Oil & Grease, Nitrate-N, Iron
- Permit: KYR00 General Industrial Stormwater Permit
- Frequency: Semi-annual or quarterly
- General Analytes: pH, TSS, Oil & Grease
- Sector J: Includes Nitrate-N, Total Recoverable Iron, Zinc
- Permit: ILR00 General NPDES Permit
- Frequency: Twice per year
- General Analytes: pH, TSS, Oil & Grease
- Sector J: pH, TSS, Oil & Grease, Nitrate-N
- Permit: MIG140000 Industrial Stormwater
- Frequency: Quarterly
- General Analytes: pH, TSS, Oil & Grease
- Sector J: Includes Total Phosphorus, Nitrate-N, Iron
- Permit: TXR050000
- Frequency: Quarterly
- General Analytes: pH, TSS, Oil & Grease
- Sector J: pH, TSS, Oil & Grease, Nitrate-N, Aluminum, Iron