The physiography, geology, and soils of Kentucky pose numerous challenges with regard to adequate on-site wastewater treatment and disposal. Conventional on-site disposal systems are commonly inappropriate based on local geology, topography, and groundwater sensitivity, and dictate the need for alternative on-site wastewater treatment and disposal systems.

In the eastern Kentucky Coal Fields, small lots, poor soils, and high-slope conditions combined with a hydrology dominated by topographically controlled, stress-relief fracture flow conditions make conventional on-site wastewater disposal ineffective. Many residents in this region rely on private and public wells and springs for their water supply. The Mississipian Plateau is dominated by karst terrain in which groundwater is vulnerable to surface and shallow subsurface land use due to rapid recharge via soil structures, (e.g. macropores) and bedrock conduits, sinks, etc. Many residents of this physiographic region utilize wells and springs as water supplies, which may be impacted by improper on-site wastewater disposal, including straight-pipes and failing septic systems. In the continental soils of the Purchase physiographic region water wells have been impacted by fecal coliform bacteria resulting from failing on-site wastewater disposal systems, juxtaposed with shallow, poorly sealed augured tile wells.

The National Small Flows Clearinghouse reports that over 40% of Kentucky’s households are not connected to municipal sewer systems. EPA estimates a 10-30% failure rate per year for on-site disposal systems. The 1998 Kentucky Report of Congress on Water Quality states that sewage is the 4th largest pollutant in the state’s waterways, with 31% of assessed streams in Kentucky are impacted by fecal coliform bacteria. The 2000 EPA Groundwater Report to Congress indicated that nitrate and bacterial contamination of wells is associated locally with ineffective on-site sewage disposal.

If Kentucky is to achieve environmental quality goals and properly protect public health these challenges must be overcome. Alternative on-site wastewater treatment options, adequate for site-specific soils and hydrogeology, must be explored if Kentucky is to overcome the physiographic, geologic, and soil challenges, as well as the associated socio-economic issues.