In Virginia, Loudoun Water (formerly the Loudoun County Sanitation Authority) approves all specifications and plans for community-based systems in new developments. The developers then deed the systems to Loudoun Water to own and operate. The agency relies heavily on natural wastewater treatment, such as septic tanks, drip irrigation, and recirculating sand filters, which are shown here. Photos: Loudoun Water
The wastewater treatment building at a subdivision in Aldie, Va., is served by a community wastewater system that disperses effluent in a low-pressure distribution system. About half of the effluent is lost to evapo-transpiration from both the grass and the soil. The other half recharges the groundwater approximately half a mile from the closest well. The wastewater treatment system consists of dual-train extended aeration package plants within a building, followed by a deep bed denitrification filter and a low-pressure distribution in aerobic drainfields.

However attractive decentralized systems are, though, what remains is the question of responsibility in the wake of a system failure.


Although in most cases developers install the community systems and operations firms are contracted for maintenance, some cities and counties operate and maintain the systems themselves.

In Loudoun County, Va., where about 1,000 of 57,000 sewer connections are decentralized, officials took matters into their own hands, dictating the terms under which decentralized systems can be installed.

The utility works with developers to ensure that design standards of their chosen vendors comply with state collection and treatment regulations and are efficient and reliable. Loudoun Water (formerly the Loudoun County Sanitation Authority) also works with the local health department that oversees the subsurface discharging systems.

The county's board of commissioners created the public utility in 1959 to provide water and wastewater services to unincorporated areas just as the historical farming community northwest of Washington, D.C., was at the verge of a boom in suburban sprawl.

“Only individual systems or community-based systems are allowed, and they are only allowed to be operated publicly,” says Todd Danielson, manager of community systems. “It comes from a history of nightmares trying to fix problems with improperly installed septic systems.”

Not until the early 1990s did the board of supervisors adopt a general plan that allows cluster developments in the formerly rural areas of the county. When property values skyrocketed at the end of the decade, developers began moving in with community-based systems.

Loudoun Water owns and operates eight community-scale systems that discharge 10,000 to 125,000 gallons/day each, and it operates another eight (which are owned largely by schools, other towns, and businesses) that discharge 4,000 to 250,000 gallons/day each. Homeowners pay Loudoun Water quarterly based on how much water their subdivision uses.

Although some states regulate decentralized community systems, there are no federal standards to ensure that developers install systems that operate properly. Loudoun County's approach — owning and operating the systems after approving design — is rare.

In addition to the sporadic state permitting issues, most community-scale systems are surface discharge systems that require a National Pollution Discharge Elimination System permit, but they also can be subsurface discharge systems, which are permitted through local health departments. There's also the question of certification — in most places, operators of decentralized systems don't need any type of certification — and oversight to ensure that private developers follow a standard.