Around the Turn of the Century, Skowhegan began to install a collection system to collect sewerage and excess rain water from its downtown area. This early collection system was a "straight-pipe" system, meaning it collected sewage and dumped it directly into the Kennebec River. Over time the system was expanded, but the means of disposal was unchanged. Beginning in the early 1960s the Town started contemplating installing a treatment facility to treat this flow before it was disposed of in the river. This effort culminated in the early 1970s with the construction of "interceptor" sewers along the north and south sides of the Kennebec River that collected the untreated wastewater and stormwater and conveyed it to a new Water Pollution Control Facility (WPCF). As this effort was progressing, Maine's own Senator Edmund Muskie was championing the Clean Water Act in congress, which was passed and signed into law by President Nixon in 1972, thus finalizing the need for the WPCF.

The interceptor sewers that were constructed in the 1970s were designed with "regulator structures", essentially overflows, to control how much of the collected water and sewerage reached the WPCF. Skowhegan's collection system is a "combined system" meaning it collects rainwater runoff (via catch basins), as well as sewerage from homes and businesses. During normal dry weather and light wet weather conditions, this combined flow is conveyed to the WPCF, treated, and discharged to the river. However, during heavier wet weather conditions (heavy rains, snow melt, etc) the regulator structures redirect a portion of this combined flow to the river. This feature was intended to protect the WPCF from high flows that could disrupt the treatment process. The flows that are redirected, without treatment, to the river are called "combined sewer overflows" (CSOs). Currently, the Skowhegan collection system includes 9 CSO regulators.

In the 1990s the Maine Department of Environmental Protection (DEP) became more concerned with CSOs everywhere in the State, including Skowhegan's. As a result, in 1997, the Town committed to implementing a two phase project that would significantly reduce the CSOs to the Kennebec River. This project, when finally completed, will reduce the Town's CSOs by nearly 97%.

The Phase I project addressed the WPCF and the collection system on the south side of the Kennebec River. The first step was an expansion of the wet weather treatment capacity at the WPCF by an additional 2,500,000 gallons per day. This effort included the installation of a new headworks facility with automatic influent screening equipment; new tanks to provide partial treatment to the increased flow; a new computerized control system for the facility to help improve the operational efficiency of the system; and equipment replacement or updates for much of the 30 year old process equipment that had reached the end of its designed life expectancy.

Phase I also reduced CSOs by separating targeted storm water collection systems and sewer systems. Essentially allowing the storm water, that is the cause of much of the "peak" wet weather flow, to go directly to the river while the sewerage still goes to the plant. This level of separation is more expensive then one would think, and as such, needs to be done judiciously. As a result four streets were targeted for this effort: Waterville Road, West Front Street, Free Street and South Street.

A final aspect of Phase I involved replacing the sewer pipe that ran along Currier Brook. It had previously been identified that this sewer was allowing significant flow from the brook to enter the collection system. Therefore, as part of Phase I the pipe was replaced.

Construction of the Phase I project began in August 2002 and was completed in June 2004. The final cost of this phase was $4,800,000.

Phase II of the project will address the collection system on the north side of the Kennebec River and further reduce combined sewer overflow activity. This Phase is discussed on the Phase II Page.