2021 MSGP for Industrial Stormwater Discharges
EPA Updates their Multi-Sector General Permit (MSGP) for Industrial Stormwater Discharges
On January 15, 2021, the U.S. Environmental Protection Agency (EPA) signed and issued a 2021 update to the Multi-Sector General Permit (MSGP) for industrial stormwater discharges. The 2021 MSGP will become effective on March 1, 2021 and will replace the 2015 MSGP. The EPA’s 2021 MSGP applies in areas of the country where EPA is the National Pollutant Discharge Elimination System (NPDES) permitting authority, including New Hampshire and Massachusetts.
Changes to the MSGP include:
- EPA requires certain operators to conduct “report-only” indicator analytical monitoring for three parameters - pH, Total Suspended Solids (TSS), and Chemical Oxygen Demand (COD) - quarterly for the duration of the permit. Evaluating these data will inform future consideration of benchmark monitoring.
- The 2021 MSGP also includes a new provision that requires certain operators to conduct “report-only” indicator analytical monitoring for polycyclic aromatic hydrocarbons (PAH) twice per year during their first and fourth years of permit coverage.
- The 2021 MSGP does not cover new industrial sources beyond those named in the 2015 MSGP. A list of covered sectors can be found in Appendix D of the 2021 MSGP listed by Standard Industrial Classification (SIC) code.
- EPA modified the benchmark monitoring thresholds for aluminum, copper, selenium, and cadmium and suspended the benchmark monitoring thresholds for magnesium and iron. The 2021 MSGP is also allowing operators who exceed the revised benchmark thresholds for discharges to freshwater for aluminum and copper to develop a facility-specific threshold value in lieu of the applicable MSGP benchmark threshold.
Key deadlines:
| Category of Facility/Operator | NOI Submission Deadline |
| Existing MSGP facility. Operators of industrial activities whose stormwater discharges were covered under the 2015 MSGP. |
No later than May 30, 2021. |
| Operator operating consistent with EPA’s No Action Assurance and submitted an Intent to Operate (ITO) form. Operators of industrial activities who commenced discharging between June 4, 2020 and March 1, 2021 and have been operating consistent with EPA’s June 3, 2020 ‘No Action Assurance for the NPDES Stormwater Multi-Sector General Permit for Industrial Activities. |
As soon as possible, but see the June 3, 2020 ‘No Action Assurance for the NPDES Stormwater Multi-Sector General Permit for Industrial Activities’ (and any updates to that document) for additional guidance on deadlines. |
| New facility without MSGP coverage. Operators of industrial activities that will commence discharging after March 1, 2021. |
At least 30 calendar days prior to commencing discharge. |
| Existing facility covered under an alternative permit. Operators seeking coverage for stormwater discharges previously covered under an individual permit or an alternative general permit. |
At least 30 calendar days prior to commencing discharge. |
| Existing MSGP facility with a new operator. New operators of existing industrial activities with stormwater discharges previously authorized under the 2021 MSGP. |
At least 30 calendar days prior to the date of transfer of control to the new operator. |
| Existing facility without MSGP coverage. Operators of industrial activities that commenced discharging prior to March 1, 2021, but whose stormwater discharges were not covered under the 2015 MSGP or another NPDES permit and have not been operating consistent with EPA’s No Action Assurance for EPA’s NPDES MSGP. |
Immediately; your stormwater discharges are currently unpermitted. |
For more information, contact Katy Ward, Aries’ Principal Engineer and head of Aries’ Environmental Compliance & Permitting Section.
January 27, 2021
