Lenah Run: A Case Study Concerning Decentralization and Communal Water and Wastewater Systems

Loudoun County, Virginia, historically a farming community located 30 miles west of Washington, DC, began experiencing major residential growth during the 1980's and became the third fastest growing jurisdiction in the country in the 1990's. In hopes to manage growth and maintain the quality of life in rural areas, the County Board of Supervisors created as an alternative to the 3 and 10 acre lot rural subdivisions the Rural Village and Rural Hamlet design concepts, where several small residential and possibly civic and commercial lots (villages only) are clustered together. The County's General Plan identifies communal water and wastewater systems as the preferred method of providing water and wastewater for residents of rural villages.As required by the County, the Loudoun County Sanitation Authority must own operate and maintain any communal water system serving 15 or more connections and any communal wastewater system serving over 2 connections. LCSA has adopted a Statement of Policy where these systems are constructed at no cost to the Authority, they are designed and constructed to standards approved by the Authority, and are financially self-sustaining.Lenah Run is the first hamlet to be constructed with communal water and wastewater systems. It is located on approximately 460 acres and has 251 single family homes planned for construction in six hamlets with five additional homes on conservancy lots. Water is provided to residents from two wells pumping a combined 175 gpm, with only sodium hypochlorite added prior to entering the distribution system. A 72,000 gallon atmospheric storage tank floats on the system to help supply water during peak use periods. Wastewater is collected through a gravity sewer that discharges into the wastewater treatment plant influent pump station. Because the Dulles Area Watershed Policy restricts effluent discharges to surface waters, the wastewater is treated in an extended aeration plant with a denitrification filter and then transferred via force main to a low pressure distribution system for discharge below ground surface.