California Draft TMDL-Based Action Levels Available for Public Comment

The California State Water Resources Control Board (State Water Board) adopted a revised NPDES General Permit for Storm Water Discharges Associated with Industrial Activities (IGP) in April 2014, which became effective last year (July 2015). Kennedy/Jenks Consultants previously discussed the permit changes on this blog in September 2014 .

Under Section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters to establish priority rankings and develop Total Maximum Daily Loads (TMDLs). A water body may become 303(d) listed in California if the State and Regional Water Quality Control Boards (Regional Water Boards) determine the water quality does not meet protective water quality criteria and standards. The pollutant(s) of concern are identified for that water body and a TMDL is developed by the US Environmental Protection Agency (EPA) or state agencies.

The revised IGP addresses 303(d) listed water bodies and associated TMDL requirements. Attachment E of the IGP lists approximately 30 water bodies in California within four (4) Regional Water Board jurisdications that are impaired by one or more parameters typically associated with industrial stormwater discharges. To avoid the development of these TMDLs delaying adoption of the IGP in 2014, the State Water Board adopted the IGP without specific TMDL values and outlined how TMDLs would be incorporated at a later date. According to the IGP, the State and Regional Water Boards are to develop proposed TMDLs for each of the pollutants of concern and water bodies listed in Attachment E of the IGP and submit the draft TMDLs for a 30-day public comment period, with the ultimate goal being adoption into the IGP.


At the end of February 2016, the Regional Water Boards listed in Attachment E began initiating the 30-day public comment periods for proposed TMDLs. For some water bodies, the associated Regional Water Board determined that the IGP-defined Numeric Action Level (NAL) was adequate and an additional TMDL was not needed for industrial stormwater dischargers. However, TMDL-based Action Levels (TALs) have been proposed for some water bodies by the associated Regional Water Boards. TALs may be applicable to stormwater discharges, authorized non-storm water discharges (NSWDs), or both. Pollutants with draft TALs include metals (copper, lead, zinc), nutrients (nitrogen compounds), and bacteria. Bacterial parameters are not currently included in the IGP. The draft TAL for a pollutant may vary by Regional Water Board and by water body.

Depending on the pollutant and the Regional Water Board, the TMDL requirements may apply to: 1) any facility with industrial activity that discharges to the 303(d) listed water body; 2) only facilities with specific Standard Industrial Classification (SIC) codes; or 3) only facilities with the potential to contribute the pollutant to their discharges.


The IGP defined two types of NALs: instantaneous and annual. Per the IGP, an instantaneous NAL applies if two or more individual samples exceed the instantaneous NAL for a parameter in one reporting year. If this occurs, the facility’s Compliance Status changes (i.e. from a Baseline Compliance Status to a Level 1 Compliance Status, or from a Level 1 Compliance Status to a Level 2 Compliance status). In comparison, the annual NAL is compared to the average of the sample results for the whole reporting year, and the facility’s Compliance Status changes if the average value exceeds the annual NAL.

Most of the draft TALs are instantaneous maximum values. According to the Regional Water Board notices, TALs are functionally the same as NALs for permit compliance purposes. The IGP only set instantaneous NALs for pH, total suspended solids (TSS), and oil & grease, so although the IGP defined annual NALs for many of the parameters with draft TALs, most of the parameters do not currently have an instantaneous NAL. For these parameters, the draft TALs are additional action levels rather than revised action levels.


The specific additional monitoring and reporting requirements associated with the proposed TMDLs vary between the Regional Water Boards, but the proposed rules typically require facilities discharging to the impaired water body to incorporate the new sampling requirements in their Monitoring Implementation Plan within six months of the TMDL being adopted. Some of the proposed TMDLs are also tied to more significant regulatory implications. As an example: facilities under the jurisdiction of the Los Angeles Regional Water Board that have TMDLs for metals would be given four months from the date the TMDL is adopted to: 1)prove their stormwater and/or authorized NSWDs do not have the potential to contribute the constituent to its facility discharges; 2) report that the facility has installed an Advanced BMP capable of retaining all stormwater and authorized NSWDs for an 85th-percentile, 24-hour event; or 3) report that the facility is already at Level 1 or Level 2 Compliance Status for the TMDL-pollutant. If the facility could not claim any of these options, the facility would automatically be upgraded to Level 1 Compliance Status and be required to submit a Level 1 Exceedance Response Action (ERA) Report within six months of the TMDL being adopted.


If the proposed TMDL requirements apply to a facility, those requirements have the potential to dramatically affect that facility’s permit compliance efforts.

  • The facility would need to add one or more new parameters to their Monitoring Implementation Plan.
  • Facilities may find it more challenging to avoid exceeding instantaneous NALs/TALs than the annual NALs, and therefore some facilities may find it more difficult to remain at Baseline Compliance Status. For example, the annual NAL for zinc is 260 micrograms per liter (ug/L), and the proposed instantaneous TAL for zinc ranges from 95 ug/L to 213 ug/L. For copper, the annual NAL is 33.2 ug/L, and proposed instantaneous TAL ranges from 3.7 ug/L to 43.3 ug/L. When the proposed TAL is lower than the annual NAL, a facility could exceed the instantaneous TAL twice without exceeding the annual NAL.
  • If a discharger is moved to a higher Compliance Status (i.e. Level 1 or Level 2), evaluation and reporting requirements are triggered that require a Qualified Industrial Stormwater Practitioner (QISP) and/or Professional Engineer (PE). This is a current requirement of the IGP, not a new requirement for the proposed TMDLs; however, the proposed TMDLs may result in an increased likelihood of these steps being required of a facility.
  • The facility may be automatically moved to Level 1 Compliance Status and required to submit a Level 1 ERA Report if they cannot claim an exemption.

While manageable, these additional requirements could make it more difficult and more expensive for some facilities to stay in compliance with the IGP. The State Water Board has started submitting the draft TMDLs to the public for commenting. The comment period end dates are provided below.

If you have questions or need QISP or PE assistance, Kennedy/Jenks staff have developed proven solutions at numerous industrial facilities and can help with developing the required plans, pollutant source identification & control, and most importantly, developing a strategy for how to comply with the IGP and prepare for future regulatory developments. We have a long list of references. Please don’t hesitate to contact us at:

Public Notices

Santa Ana Regional Water Quality Control Board, Deadline March 24, 2016:

San Diego Regional Water Quality Control Board, Deadline March 31, 2016:

San Francisco Regional Water Quality Control Board, Deadline March 31, 2016:

Los Angeles Regional Water Quality Control Board, Deadlines March 31, 2016 and April 1, 2016:

Ventura Coastal Watershed Management Area, Deadline April 7, 2016: Ventura Coastal WMA PN and factsheet

Proposed Addition of TMDL for Calleagus Creek Watershed:

Proposed Addition of TMDL for Oxnard Drain No 3 for Pesticides, PCBs, and sediment toxicity: TMDL for Toxics in Oxnard Drain No 3 (final)