South Carolina Industrial Stormwater – On the Tides of Change

The South Carolina Department of Health and Environmental Control (SCDHEC) has issued the Industrial Stormwater General National Pollutant Discharge Elimination System (NPDES) Permit (SCR000000) on May 26, 2022, and the permit became effective on July 1, 2022. Upon the permit’s effective date, a recertification Notice of Intent (NOI) is required from all existing coverage holders within the following 90 days. The 2016 permit expired on September 30, 2021, but remained effective until May 26, 2022, due to language in Section 1.3.2 of the 2016 permit. SCR000000 is based on United States Environmental Protection Agency (U.S. EPA) NPDES Multi-Sector General Permit (MSGP) for industrial stormwater, published on January 15, 2021.

There are four key updates to be mindful of with SCR000000 and all updates are consistent with information found in U.S. EPA’s MSGP.

• Addition of year 4 “checkups” to benchmark monitoring,
• Addition of year 4 “checkups” to impaired waters,
• Updates to benchmark values of metal pollutants, and
• Switch to uniform reporting periods for all permit Sectors.

SCR000000 now includes a fourth year “checkup” to quarterly benchmark monitoring. In addition to the existing benchmark sample collection during the first year of permit coverage, quarterly samples must now be collected during the fourth year of permit coverage as well. The purpose of the checkup is to verify that operators possess current industrial stormwater discharge and control measure data throughout the lifespan of the permit. In addition, potentially adverse effects from changes in facility operations can be more easily identified over the span of the permit. Lastly, the requirement is not impacted due to results found in the first three years of SCR000000 coverage – no matter what the results of the first year’s benchmark testing are each facility will still be required to sample again in the fourth year.

The new permit also adds a similar fourth year “checkup” for impaired waters monitoring. Impaired waters by definition do not have an U.S. EPA approved or established Total Maximum Daily Loads (TMDL); this requirement is often referred to as Section 303(d) monitoring. Again, the requirement to sample in the fourth year is not impacted by monitoring results found in the first three years of SCR000000 coverage.

The permit has updated multiple pollutant benchmark values for metals, including cadmium, selenium, and silver. These changes have been made in accordance with the updated benchmark values from U.S. EPA’s updated MSGP. The value for selenium is now separated between flowing (lotic) and standing (lentic) Freshwater bodies. The values for cadmium and silver in Freshwater have been updated. While the Saltwater values for all three pollutants is unchanged from the 2016 permit.

The facility will use uniform reporting periods across all sectors within the numeric effluent limit discharge monitoring reports (DMR). This change removes the staggered reporting periods previously used in the 2016 permit. The quantity of DMRs is to remain stable for the near future and SCDHEC considers their number manageable for all coverage holders.

With the issuance of SCR000000 all existing coverage holders are required to submit a recertification of Notice of Intent (NOI). What is the due date for the NOI? The NOI is due within 90 days of SCR000000’s effective date (July 1, 2022) to maintain current NPDES stormwater coverage. All NOIs and permits are to be submitted electronically through ePermitting and be updated to meet compliance with SCR000000. Site’s stormwater pollution prevention plans (SWPPP) must also be updated to reflect changes to SCR000000.

ALL4 is tracking all SCDHEC industrial stormwater updates and is here to assist you and your facility with industrial stormwater compliance. If you have questions or concerns about SCR000000 compliance and renewal, please contact me at ages@all4inc.com or Anna Richardson at arichardson@all4inc.com.