Loudoun Water Opens Water Treatment Plant

On Tuesday, May 21, 2019 Loudoun Water held the formal opening ceremony for their Trap Rock Water Treatment Facility, Virginia’s most advanced water treatment plant. The Trap Rock Water Treatment Facility cost $130 million and is located south of Leesburg along the Dulles Greenway. The Trap Rock plant treats water drawn Potomac River, transports it through a 6-mile underground pipeline and now cleans it in the commonwealth’s only two-step ozone treatment system. 

from Loudoun Water 

Loudoun Water provides drinking water and wastewater services to over 200,000 people in Loudoun County. Loudoun County is one of the fastest growing counties in the United States with a total population of 398,000 in 2017. Maximum day water demands are projected to grow from the current 40 million gallons per day to 90 million gallons per day by 2040. Loudoun’s water has been supplied by the Beaverdam and Goose Creek reservoirs (and the Goose Creek water treatment plant) which were owned until recently by Fairfax City, and from Fairfax County, which pulled water from the Potomac River, treated it and sold it to Loudoun Water. Five years ago Loudoun Water purchase all the Fairfax county owned water assets in Loudoun County and began negotiations to draw water directly from the Potomac River.

With the completion of the Potomac River water intake and pumping station and the Trap Rock Water Treatment Plant for the first time Loudoun Water is directly tapping the Potomac River to meet their water demands. The Potomac River is the primary water supply source for the Washington metropolitan area providing almost 95% of the drinking water to around 6 million people at home or in their workplaces. River water is drawn by the Washington Aqueduct Division of the U.S. Army Corps of Engineers (WAD), the Fairfax County Water Authority (FCWA), the Washington Suburban Sanitary Commission (WSSC), and City of Rockville and now by Loudoun Water. 

from Loudoun Water

Though the population of the Washington metropolitan area has grown significantly since 1990 (from 3.9 million to 6.0 million), over the same period the water use in the region has remained fairly constant. The average daily water demand is forecast to be under 500 million gallons a day. Per capita water use has not only fallen in our region, but throughout the United States. Nonetheless with continued population growth and climate change is necessary that the region increase their water storage.

The Potomac River flow fluctuates with season and weather. The Interstate Commission on the Potomac River Basin (ICPRB) helps the water companies manage the river’s water resources. The ICPRB was born out of the severe and extended drought in the 1960's when water withdrawals by the three major water companies from the Potomac reduced flows to such an extent that the River practically ran dry, leaving only mud between Great Falls and the tidal river. Ultimately (after more than a decade) the ICPRB was created and the Jennings Randolph Reservoir was built to manage the use of the Potomac River and to ensure that there is enough flow for essential services like wastewater assimilation and habitat maintenance. The ICPRB monitors river flows and water withdrawals to ensure the 100 million gallons per day minimum flow at Little Falls.

Loudoun Water has joined in the Low Flow Allocation Agreement (LFAA), which allocates the amount of water each supplier can withdraw from the Potomac River in the event that total flow is not sufficient to meet all needs and the Water Supply Coordination Agreement (WSCA), which provides for coordinated operations during periods of low flow and regular planning studies managed by the ICPRB. In addition, this year, Loudoun Water will open the first phase of it’s water banking system. Loudoun Water will convert former Luck Stone quarries to storage reservoirs. The first (opening this year) will hold 1 billion gallons for emergency use; ultimately 8 billion gallons will be stored in quarries now mined by Luck Stone north of the treatment plant.