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• &EPA • • Stormwater Phase II Final Rule Fact Sheet Series Overview 1.0 - Stormwater Phase II Final Rule: An Overview Small MS4 Program 2.0 - Small MS4 Stormwater Program Overview 2.1 - Who's Covered? Designation and Waivers of Regulated Small MS4s 2.2 - Urbanized Areas: Definition and Description Minimum Control Measures 2.3 - Public Education and Outreach 2.4 - Public Participation/ Involvement 2.5 - Illicit Discharge Detection and Elimination 2.6 - Construction Site Runoff Control 2.7 - Post - Construction Runoff Control 2.8 - Pollution Prevention /Good Housekeeping 2.9 - Permitting and Reporting: The Process and Requirements 2.10 - Federal and State - Operated MS4s: Program Implementation Construction Program 3.0 - Construction Program Overview 3.1- Construction Rainfall Erosivity Waiver Industrial "No Exposure" 4.0 - Conditional No Exposure Exclusion for Industrial Activity United States Office of Water EPA 833 -F -00 -007 Environmental Protection (4203) January 2000 (revised December 2005) Agency Fact Sheet 2.5 Stormwater Phase 11 Final Rule Illicit Discharge Detection and Elimination Minimum Control Measure his fact sheet profiles the Illicit Discharge Detection and Elimination minimum control 1 measure, one of six measures the operator of a Phase II regulated small municipal separate storm sewer system (MS4) is required to include in its stormwater management program to meet the conditions of its National Pollutant Discharge Elimination System (NPDES) permit. This fact sheet outlines the Phase II Final Rule requirements and offers some general guidance on how to satisfy them. It is important to keep in mind that the small MS4 operator has a great deal of flexibility in choosing exactly how to satisfy the minimum control measure requirements. What Is An "Illicit Discharge "? Federal regulations define an illicit discharge as "...any discharge to an MS4 that is not composed entirely of Stormwater...'' with some exceptions. These exceptions include discharges from NPDES - permitted industrial sources and discharges from fire - fighting activities. Illicit discharges (see Table 1) are considered "illicit" because MS4s are not designed to accept, process. or discharge such non - stormwater wastes. Why Are Illicit Discharge Detection and Elimination Efforts Necessary? Discharges from MS4s often include wastes and wastewater from non - stormwater sources. A study conducted in 1987 in Sacramento. California. found that almost one -half of the water discharged from a local MS4 was not directly attributable to precipitation runoff. A significant portion of these dry weather flows were from illicit and /or inappropriate discharges and connections to the MS4. Table 1 Sources of Illicit Discharges Sanitary wastewater Effluent from septic tanks Car wash wastewaters Improper oil disposal Radiator flushing disposal Laundry wastewaters Spills from roadway accidents Improper disposal of auto and household toxics Illicit discharges enter the system through either direct connections (e.g., wastewater piping either mistakenly or deliberately connected to the storm drains) or indirect connections (e.g., infiltration into the MS4 from cracked sanitary systems. spills collected by drain outlets. or paint or used oil dumped directly into a drain). The result is untreated discharges that contribute high levels of pollutants, including heavy metals, toxics. oil and grease. solvents, nutrients, viruses, and bacteria to receiving waterbodies. Pollutant levels from these illicit discharges have been shown in EPA studies to be high enough to significantly degrade receiving water quality and threaten aquatic. wildlife, and human health.