On November 6, 2018, the State Water Resources Control Board adopted an amendment to the National Pollutant Discharge Elimination System General Permit for Storm Water Discharges Associated with Industrial Activities (General Permit). The General Permit Amendment addresses the implementation of previously-adopted Total Maximum Daily Loads (TMDLs), the new federal Sufficiently Sensitive Methods Rule, and statewide Compliance Options. These changes take effect on July 1, 2020.

Why the amendment to the General Permit?

As outlined in the General Permit, TMDLs are regulatory tools that provide the maximum amount of a pollutant from potential sources in the watershed that a water body can receive while attaining water quality standards. A TMDL is defined as the sum of the allowable loads of a single pollutant from all contributing point sources (the waste load allocations) and non-point sources (load allocations), plus the contribution from background sources. (40 C.F.R. § 130.2, subd. (i).)

However, a TMDL is not self-implementing so the State and Regional Water Boards are required to implement TMDLs through permits, enforcement orders, and/or Water Code section 13267 or 13383 Orders. (40 C.F.R. § 122.44(d)(1)(vii).) Attachment E of the General Permit listed the watersheds with U.S. EPA-approved and U.S. EPA-established TMDLs that include TMDL requirements for Dischargers covered by the General Permit. The General Permit Amendment was adopted in order to incorporate TMDL-specific permit requirements for the TMDLs listed in Attachment E.

What you need to know:

First, in terms of the TMDLs, changes include adoption of TMDL-specific Numeric Action Levels (TNALs) and Numeric Effluent Limitations (NELs) applicable to discharges to water bodies for which industrial stormwater waste load allocations (WLAs) have been assigned. Responsible Dischargers, as defined in Attachment C (Glossary) of the General Permit Amendment, will be required to comply with the new TMDL-specific discharge requirements. For those Responsible Dischargers located in an area where the local Regional Board has adopted a Basin Plan setting TMDLs to impaired water bodies, this will prove to be a key change in the General Permit that you will need to address well in advance of July 1, 2020.

Second, the General Permit Amendment updates monitoring requirements per the new U.S. EPA-approved Use of Sufficiently Sensitive Test Methods Rule. This requires Dischargers regulated by the General Permit to use analytical methods that detect and quantify pollutants at or below applicable water quality criteria or permit limitations.

Lastly, the General Permit Amendment provides statewide Compliance Options that grant compliance with receiving water limitations, some discharge prohibitions, and most effluent limitations and excuse permittees from a variety of General Permit requirements, including NAL and ERA requirements, in exchange for implementation of on-site and/or regional stormwater capture best management practices. What this means is that the statewide Compliance Options provide all industrial storm water dischargers regulated by this General Permit additional optional avenues for compliance through options such as:

  • On-site capture and use, and/or infiltration of industrial storm water discharges, up to and including the 85th percentile 24-hour daily storm volume, or
  • Participation in agreements with local jurisdictions or other private entities to capture and use, and/or infiltrate industrial storm water discharges, up to and including the 85th percentile 24-hour daily storm volume, off-site as approved by the applicable Regional Water Quality Control Board. For more information, the State Water Resources Control provides a useful FAQ here.

For assistance with your continued compliance with the General Permit, please contact Missy Foster (melissa.foster@stoel.com, 916.319.4673), Michael Mills (michael.mills@stoel.com, 916.319.4642), or Parissa Florez (parissa.florez@stoel.com, 858.794.4106).

More information about Stoel Rives’s water quality practice may be found here.