Monitoring & Corrective Action
The permit requires the permittee to conduct stormwater sampling at least once a quarter.
Generally, you must sample discharges from the first fall storm event each year (first time after October 1st that precipitation occurs and results in a stormwater discharge from the facility) and sample within the first 12 hours of stormwater discharge events once per quarter. You need to keep documentation with the sampling records as well as reasons why you could not collect samples with the first 12 hours of stormwater discharge events.
Permittees must follow the specific guidelines set forth in the permit for conducting stormwater samples. See the Industr style=”font-size: 10px; border-bottom: 1px solid black;”ial Stormwater General Permit (ISWGP) for more specific guidelines.
| Parameter | Turbidity | pH | Oil Sheen | Copper | Zinc |
| Units | NTU | Standard Units | Yes/No | µg/L | µg/L |
| Benchmark | 25 | Between 5.0 & 9.0 | No Visible Oil Sheen | Western WA 14; Eastern WA 32 | 117 |
| Analysis | EPA 180.1 Meter | Meter/Paper | N/A | EPA 200.8 | EPA 200.8 |
| Laboratory Quantitation Level | 0.5 | ± 0.5 | N/A | 2 | 2.5 |
| Min Sampling Frequency | 1/quarter | 1/quarter | 1/quarter | 1/quarter | 1/quarter |
Above you will find a table concerning benchmarks and sampling requirements for industr style=”font-size: 10px; border-bottom: 1px solid black;”ial facilities covered under this permit. Additional sampling requirements and guidelines appear in the ISWGP.
If you exceed any applicable benchmark value you must complete a Level 1 Corrective Action for each parameter exceeded. If you exceed any applicable benchmark value for any two quarters during a calendar year you must complete a Level 2 Corrective Action and if you exceed any benchmark value for any three quarters during a calendar year you must complete a Level 3 Corrective Action. See permit for greater details.