EPA’s 2021 Multi-Sector General Permit (MSGP) Effective March 1, 2021

The U.S. EPA issued the 2021 stormwater Multi-Sector General Permit (MSGP) on January 15, 2021.  Facilities that are covered under the EPA’s MSGP must file a new Notice of Intent (NOI) to be covered under the new permit no later than May 30, 2021.  States with their own MSGPs will likely incorporate features/aspects of the EPA 2021 MSGP.  Some notable new features include:

• Requirement for benchmark monitoring for pH, total suspended solids (TSS), and chemical oxygen demand (COD) for any subsectors currently without sector-specific benchmarks (this applies to roughly 22 subsectors).
• Benchmark analytical monitoring moves to quarterly; however, reduced monitoring frequencies are permitted if no benchmark exceedances are detected during the first year.
• Additional Implementation Measures (AIM) (e.g., enhanced BMPs) will be required when benchmark exceedances are reported.

EPA's public informational webinar about the new 2021 MSGP on February 18, 2021, is already full, but another scheduled webinar is coming soon.