Project At A Glance:
Small leaks from sanitary sewer pipes can add up to create large pollution problems. The Illicit Discharge Detection Elimination study performed by Watershed sought to find as many of those leaks as possible to provide an expedient solution to a persistent problem.

Client: VT DEC, City of St. Albans

Partners: Center for Watershed Protection, Lakeside Environmental Group

Location: City of St. Albans, VT


In 2000, the Vermont Department of Environmental Conservation’s Ecosystem Restoration Program began to implement the Illicit Discharge Detection and Elimination (IDDE) program. The program is designed to find discharges of wastewater or industrial process water to the stormwater-only sewer systems. These ‘leaks’ from wastewater and industrial water can contain a variety of harmful pollutants that should be treated before discharge. Watershed was chosen by the City of St. Albans, VT to perform the IDDE study.

This work required the investigation of over one hundred known stormwater outfalls along Stevens and Rugg Brooks, as well as minor tributaries in the watershed. Along with our partners the Center for Watershed Protection and Lakeside Environmental Group, Watershed’s team walked all concerned waterway stretches during dry weather using high-accuracy GPS units to mark the locations of all outfalls.

Outfalls, once located, are then tested for a variety of potential pollutants such as E. coli, optical brighteners (typically found in laundry detergents), fluoride, and nutrients, specifically phosphorous. If any pollutants of concern were found, Watershed then attempted to locate the ‘leak’ by conducting testing upstream from the outfall, or using smoke or dye-testing from suspected discharge points.

As a result of this project Watershed was able to identify many illicit discharges within the City’s jurisdiction and help correct them, saving the City money and ensuring that the riparian ecosystem bore less stress than before.