Note: Monitoring requirements are site specific. Review the monitoring requirements letter that came with your 1200-Z permit for full information including required parameters and associated concentrations for your facility.
General monitoring and sampling requirements
- The monitoring year runs from July 1 of this year to June 30 of the following year. For example: July 1, 2024 to June 30, 2025.
- Sampling occurs four times per year. Two samples must be taken on or before December 31, and two samples must be taken on or after January 1.
- Samples must be collected at least 14 days apart.
- Take samples during the first 12 hours of a discharge event or as soon as practicable.
- Take samples at locations as described in your Stormwater Pollution Control Plan (SWPCP). All discharge points must be sampled, unless they drain an area without industrial activities (such as an employee parking) or if the discharge point has been determined to be substantially similar to other monitored discharge point(s).
- Collect discharge sample at each discharge point once per month to conduct visual observations. Visual observations must also be done at discharge points that have been deem substantially similar to other monitored discharge point(s).
- Laboratory analysis and sample collection must be conducted in accordance with requirements in 40 CFR 136.
- pH must be analyzed with a calibrated digital meter within 15 minutes of sample collection.
- Sample results that do not meet statewide benchmarks, sector-specific benchmarks or impairment pollutant monitoring concentrations require corrective actions.
Discharge Monitoring Report Requirements
All monitoring results from samples collected at monitoring points identified in the SWPCP must be submitted on a Discharge Monitoring Report according to the schedule below. Failure to submit a report is a permit violation even if the monitoring did occur. DMRs must be postmarked with original signature by the due date.
| Reporting Quarter | Sample Collection Timeframe | Report Due Date |
|---|---|---|
| Quarter 1 | July – September | Nov. 15 |
| Quarter 2 | October – December | Feb. 15 |
| Quarter 3 | January – March | May 15 |
| Quarter 4 | April – June | Aug. 15 |
Statewide Benchmarks
(all sites, based on your georegion)
| Parameter | Columbia River Benchmark | Willamette Valley Benchmark | Columbia Slough Benchmark | Portland Harbor Benchmark | Hold Time |
|---|---|---|---|---|---|
| pH | 6.0-9.0 s.u. | 5.5-9.0 s.u. | 5.5-9.0 s.u. | 5.5-9.0 s.u. | 15 minutes |
| Total Suspended Solids (TSS) | 100 mg/L | 100 mg/L | 30 mg/L | 30 mg/L | 7 days |
| Copper (Cu) | 0.023 mg/L | 0.015 mg/L | 0.017 mg/L | 0.015 mg/L | 6 months if preserved |
| Lead (Pb) | 0.21 mg/L | 0.11 mg/L | 0.10 mg/L | 0.24 mg/L | 6 months if preserved |
| Zinc (Zn) | 0.35 mg/L | 0.14 mg/L | 0.24 mg/L | 0.24 mg/L | 6 months if preserved |
| E. coli | n/a | n/a | 406 organisms/100 ml | n/a | 8 hours |
| Biological Oxygen Demand (BOD) | n/a | n/a | 24 mg/L | n/a | 48 hours |
| Phosphorus (P) | n/a | n/a | 0.16 mg/L | n/a | 28 days |
Sector-specific Benchmarks
Relevant to all sites with certain SIC codes.
Many industry types have additional SIC code-based monitoring requirements and associated benchmarks. These requirements are found in Schedule E of the permit.
Impairment Pollutants
Each facility discharges stormwater to a specific water body. If the water body is on DEQ’s 303(d) list of impaired water bodies for certain pollutants, monitoring is required for the associated impairment pollutants listed for that water body.
- These pollutant parameters have different corrective action requirements if exceeded and can escalate to narrative or numeric effluent limits (see the Corrective Actions for Impairment Pollutant Monitoring Concentrations section below).
- Narrative and numeric effluent limits must be met within a specified timeframe and have additional associated reporting requirements.
- An exceedance of a numeric effluent limit is an enforceable violation. The table below is based on the 2022 integrated report 303(d) list for Portland area receiving water bodies only and contains the pollutant monitoring that can escalate to a narrative or numeric effluent limit. If you were assigned coverage under the permit prior to Sept. 1, 2022, you are subject to the 2018/2020 303(d) list. For the most accurate in-formation please reference your monitoring requirements letter.
| Receiving Water Body | Parameter | Pollutant Concentration | Potential Effluent Limit Escalation Type |
|---|---|---|---|
| Columbia Slough | Total Iron | 10 mg/L | Narrative Limit |
| Tributaries to Columbia Slough | Total Copper | 0.017 mg/L | Numeric Limit |
| Fairview Creek | Total Copper | 0.017 mg/L | Numeric Limit |
| Johnson Creek | Total Iron | 10 mg/L | Narrative Limit |
| Total copper | 0.015 mg/L | Numeric Limit | |
| Columbia River | n/a | n/a | n/a |
| Saltzman Creek | n/a | n/a | n/a |
Corrective Actions
Corrective actions for statewide benchmarks and visual observations
Tier 1 Corrective Action
Required for any exceedance of a statewide benchmark, sector-specific benchmark, or if visual observations show evidence of stormwater pollution. Review Schedule A.11 for a complete list of requirements. In summary, you need to:
- Investigate the cause of the elevated pollutant levels, determine if the SWPCP is being followed, and prepare a Tier 1 corrective action report within 30 days of receiving the sample results. Retain the report onsite for three years.
- The report needs to contain corrective actions to improve stormwater quality and a date of implementation.
- You must implement corrective actions before the next rain event, if possible, or no later than 30 calendar days after receiving the sample results.
Tier 2 Corrective Action
Required if the Geometric Mean Calculation of qualifying samples results in any full monitoring year is greater than the associated statewide benchmark. The geometric mean of sample results collected during the monitoring year must be calculated each year and is due with the August discharge monitoring report. Review Schedule A.12 of the permit for a complete list of requirements. In summary, you will need to:
- Prepare and submit a Tier 2 Report which includes treatment measures or a Tier 2 Mass Reduction Waiver (both require a stamp from an engineering professional) by Dec. 31 (6 months after the full reporting year).
- Once approved, fully implement the Tier 2 Corrective Actions by Sept. 30 (1 year and 9 months after the report submittal deadline).
Corrective actions for sector-specific benchmarks
Tier 1 Corrective Action is required for any exceedance of a sector-specific benchmark (see above).
Corrective Actions for Impairment Pollutant Monitoring Concentrations
Zinc, Copper, Lead and pH
- Single exceedance: No response required.
- Escalation to Water Quality Based Numeric Effluent Limit: If two consecutive results exceed the monitoring concentration or one result is greater than two times the concentration (zinc, copper and lead), the impairment monitoring concentration becomes an enforceable limit. Review Schedule A.13. In summary, you will need to:
- Notify the City within 30 days of receiving the monitoring results.
- Request a compliance schedule per Schedule C of the permit or future exceedances will be a permit violation.
E. coli and Iron
- Single exceedance: No response required.
- Escalation to Water Quality Based Narrative Effluent Limit: If two consecutive results exceed the impairment monitoring concentration, narrative requirements must be met. Review Schedule A.13. In summary, you will need to:
- Notify the City within 30 days of receiving the monitoring results.
- Implement the narrative controls within 90 calendar days from receiving the monitoring results.