In his presentation at the June 15 ISRI Safety & Environmental Council (ISEC) Meeting, David Wagger, Ph.D., ISRI’s chief scientist and director of environmental management, discussed four new developments to stormwater management. Changes to the federal 2021 Multi-Sector General Permit (MSGP) topped the list, followed by new federal guidance on a group of chemicals known as PFAS and the National Pollutant Discharge Elimination System (NPDES). A Supreme Court decision about discharges to groundwater and the ongoing debate over what makes up the Waters of the United States (WOTUS) are additional areas of concern for recyclers.

2021 MSGP

For 2015 MSGP permittees, notice of intent for the 2021 MSGP, which became effective March 1, was due May 30. Changes include a requirement to post a sign indicating permit and other information. Selection and design elements for stormwater control measures now include so-called major events. “The idea is to require facilities to think about how they can move equipment and materials in a way that will reduce environmental impact in the case of a major storm event such as torrential rain,” Wagger explains.

Two categories of new indicator monitoring include a suite of 16 polycyclic aromatic hydrocarbons (PAHs) for permittees using coal-tar sealants in areas of industrial activity, and the trio of chemical oxygen demand (COD), total suspended solids (TSS), and pH for industrial sectors and subsectors that did not have benchmark monitoring under the 2015 MSGP. Benchmark monitoring is now required in years one and four of the permit, unless additional monitoring is required because of a benchmark exceedance. Iron is no longer a benchmark parameter. Applicable benchmarks for copper and aluminum now include an option for facility-specific benchmarks. The Environmental Protection Agency has software to help determine your facility’s copper and aluminum benchmarks, if necessary.

Perhaps the most important change is the new Additional Implementation Measures (AIM) framework. Each facility starts at the Baseline Level in Year One of the permit. Over the first year of quarterly monitoring, any average in a monitored outfall that exceeds the benchmark moves your operation to Level 1 for the exceeded parameter in that outfall. It triggers EPA review of your Stormwater Pollution Prevention Plan (SWPPP) and installing necessary Stormwater Control Measures (SCM) for that parameter in that outfall. A repeated benchmark exceedance over subsequent annual quarterly monitoring raises the AIM level. Each higher level has a more-stringent required response. “The idea of AIM is to get facilities meeting their benchmarks, as necessary, through whatever SCMs, including structural ones, are required,” Wagger explains. While the 2021 MSGP applies only in certain states and federal areas, most states eventually adopt some or all of the federal MSGP for their own industrial stormwater general permits.

PFAS in Permitting

A new federal interim strategy to address PFAS in stormwater permitting includes, “permit requirements for phased-in monitoring and stormwater pollutant control, as appropriate, taking into consideration when PFAS are expected to be present in stormwater discharges” in the workgroup recommendations. This strategy includes the following intended deliverables:

  • Posting relevant NPDES information on the PFAS website and NPDES Permit Writers’ Clearinghouse, expected in June 2021; and
  • Publishing a PFAS permitting compendium with examples of EPA and state permit conditions, expected in the third quarter of 2021.

One example of this strategy seems to be EPA’s updated 2021 MSGP industrial-sector factsheets for recycling and auto salvage that contain references to PFAS. “There’s at least a marker that has been put down in the federal world on PFAS, and I believe all the sectors have similar types of language added to their factsheet,” Wagger says.

Another example is Maryland’s draft 20-SW industrial general permit that requires identifying, listing, and addressing in a facility’s SWPPP potential sources of certain PFAS that could end up in stormwater runoff. ISRI commented on Maryland’s permit, including this proposed PFAS requirement. “[Recyclers] typically aren’t notified if there are PFAS in materials that we receive or even in supplies, lubricants, and other things that might be used as parts of the operation,” Wagger notes. Concerning PFAS monitoring in a facility’s stormwater discharges, there is not yet an approved analytical method for measuring PFAS in stormwater samples.


The Supreme Court in May 2020 handed down a ruling related to the Clean Water Act that may interest recyclers. In County of Maui v. Hawaii Wildlife Fund, the court held the law requires a permit for a discharge through groundwater to a WOTUS if it’s the “functional equivalent” of a direct discharge from a “point source,” like a pipe or channel.

The court articulated seven potentially relevant factors to consider when determining what constitutes a functional equivalent of a direct discharge. Although transit time and distance traveled will be the most important factors in most cases, the court emphasized that the facts of a given case would determine each factor’s relevance and relative weight.

The EPA’s guidance on the ruling boils down to two outcomes, Wagger says: If your discharge to groundwater seems to be a functional equivalent, then ask your permitting authority about permitting. If a stormwater control measure, such as a retention pond, removes pollutants from stormwater before it can discharge to groundwater, then it’s less likely to be a functional equivalent requiring an NPDES permit.

New developments to WOTUS may expand its definition. The Obama and Trump administrations had differing views of what constitutes WOTUS under the Clean Water Act. This is likely most relevant for stormwater permitting in rural areas. The Biden administration is reviewing the Trump Administration’s Navigable Waters Protection Rule, which reduced the scope of federal waters relative to the Obama Administration’s July 2015 WOTUS revision. Both versions exclude stormwater treatment systems from WOTUS. Though it’s unclear what the Biden administration will include in the new WOTUS, “I think our exclusion for stormwater treatment systems will hold,” Wagger reassures.

TRI Calls

Toxics Release Inventory (TRI) reporting is an EPA regulation requiring industrial and federal facilities to report toxic chemical releases, including pollution prevention activities. July 1 is the deadline for reportable activity during the previous calendar year. Though not applicable to the recycling industry, TRI likely affects recyclers’ suppliers. Wagger says suppliers may contact recyclers before the deadline asking for recyclers’ Resource Conservation and Recovery Act (RCRA) ID numbers. “If you get these calls, it’s not a scam. The TRI reporting form asks for RCRA ID numbers,” Wagger says. “If your facility has a RCRA ID number, provide it to them. If it doesn’t have one, tell them to put ‘NA’ [Not Applicable]. If you don’t know, you can call me or look it up on EPA’s ECHO database.”

You can contact Wagger at (202) 662-8533 or

Photo courtesy of Timothy L. Brock on Unsplash.


Dan Hockensmith

Dan Hockensmith

I'm a native Ohioan who since 2014 has called Maryland home. My background includes print, broadcast, and digital journalism; government contracting; and marketing communications.