Upper Occoquan Service Authority (UOSA)
Advanced Water Treatment Plant

In the late 1960’s, the opening of a major highway created a suburban area convenient to people working in Washington, D.C. The attractiveness and accelerated growth soon created water quality problems in the Occoquan Reservoir.

In 1978, The Upper Occoquan Service Authority was formed and the construction of a state of the art advanced water reclamation plant replaced 11 failing wastewater treatment plants.  The initial ten million gallons per day (mgd) capacity of UOSA was increased to 32 mgd, and a major expansion to 54 mgd has been completed.

The plant has continually met all standards for reliability and water quality. The discharges from the plant are a source of drinking water supply for over one million people. After 30 years of highly successful operations, UOSA reclaimed water is an increasingly important component of the drinking water supply strategy for the Washington metropolitan area.