Page 99 - California Stormwater Workshop Handouts

Industrial General Permit Fact Sheet

buildings, or pavement, or (2) fluid, particulate or solid materials that have spilled,
leaked, or been disposed of improperly.

Some NSWDs are not directly related to industrial activities and normally discharge
minimal pollutants when properly managed. Section IV of this General Permit provides
a limited list of NSWDs that are authorized if Dischargers implement BMPs to prevent
contact with industrial materials prior to discharge. The list in Section IV is similar to the
list provided in the 2008 MSGP but does not include pavement and external building
surfaces washing without detergents. These two items are not included because the
Discharger is responsible to reduce or prevent pollutants in storm water discharges from
paved areas and buildings associated with industrial activities. Since industrial
materials and non-industrial material likely co-exist, the washing of paved areas and
external building surfaces may result in discharges of pollutants associated with
industrial activities. In addition, washing activities generally occur during dry-weather
periods when receiving water flows are lower than wet-weather periods. Wash waters
are likely to discharge in higher concentrations than would occur if these pollutants were
naturally discharged during a storm event. The discharge of high concentration wash
water during a time of dry-weather flows is inconsistent with the goal of protecting
receiving waters. These discharges are, therefore, considered unauthorized NSWDs.
Similar to the 2008 MSGP, firefighting related discharges are not subject to this General
Permit.

A major required element of the SWPPP is the identification and measures for
elimination of unauthorized NSWDs. Unauthorized NSWDs can contribute a significant
pollutant load to receiving waters. Measures to control spills, leakage, and dumping can
often be addressed through BMPs. This General Permit’s BMP requirements for
NSWDs remain essentially unchanged from the previous permit other than the
increased frequency of required visual observations from quarterly to monthly. See
Section XI.A.1 of this General Permit.

D. Effluent Limitations

1. Technology-Based and Water Quality-Based Effluent Limitations

CWA Section 301(b)(1)(C) requires that discharges from existing facilities must, at a
minimum, comply with technology-based effluent limitations based on the
technological capability of Dischargers to control pollutants in their discharges.
Discharges must also comply with any more stringent water quality-based limitations
necessary to meet water quality standards in accordance with CWA Section
301(b)(1)(C). Water quality-based limitations are discussed in Section E of this Fact
Sheet titled “Receiving Water Limitations.” Both technology-based effluent
limitations and water quality-based limitations are implemented through NPDES
permits. (CWA sections 301(a) and (b).)

2. Types of Technology-Based Effluent Limitations

All NPDES permits are required to contain technology-based effluent limitations

(TBELs). (40 C.F.R. §§122.44(a)(1) and 125.3.) TBELs may consist of effluent

limitations guidelines (ELGs) established by U.S. EPA through regulation, or may be

developed using best professional judgment on a case-by-case basis.

Order 2014-0057-DWQ 15