Source Tracking of Inappropriate Discharges to Storm Drainage Systems

This paper describes procedures that have been used to identify sources of inappropriate (“illicit”) discharges in storm drainage systems. Also included is a review of emerging techniques that may also be useful, especially in future years as they become more accessible and become proven technologies. This paper also describes a series of tests where the original methods developed previously for EPA (Pitt, et al. 1993), along with selected new procedures, were examined using almost 700 stormwater samples collected from telecommunication manholes from throughout the U.S. About ten percent of the samples were estimated to be contaminated with sanitary sewage using these methods, similar to what is expected for most stormwater systems. The original methods are still recommended as the most useful procedure for identifying contamination of storm drainage systems, with the possible addition of specific tests for E. coli and enterococci and UV absorbance at 228 nm. Most newly emerging methods require exotic equipment and unusual expertise and are therefore not very available, especially at low cost and with fast turn-around times for the analyses. These emerging methods may therefore be more useful for special research projects than for routine screening of storm drainage systems. The Center for Watershed Protection (CWP) and Dr. Robert Pitt with the University of Alabama are currently being funded by EPA to complete a technical assessment of techniques and methods for identifying and correcting illicit and inappropriate discharges geared towards NPDES Phase II communities. The project has a two year duration. In the first year, most of our effort will be directed to collecting data. The most cost effective and efficient techniques will also be identified during this initial project period. In the second project year, the project team will develop draft guidance on methods and techniques to identify and correct illicit connections, test the efficacy of the draft guidance in four communities, complete a final “User’s Manual for Identifying and Correcting Illicit and Inappropriate Discharges,” and conduct training and dissemination. This project started in late summer, 2001.