Glossary

902 KAR 10:085: The Kentucky administrative regulation governing on-site sewage disposal systems. It sets design, construction and siting standards that local health departments administer.

Absorption Field: The area where treated wastewater is released into soil for final filtration. Also called a lateral field or leach field.

ATU (Aerobic Treatment Unit): A system that introduces air so aerobic bacteria treat wastewater. Used where soil conditions won't support a conventional gravity system.

Baffle: A barrier inside the septic tank controlling flow between compartments and keeping solids from reaching the field. A failed baffle often produces what looks like field failure.

Certified Installer: In Kentucky, an individual certified under KRS 211.357 and 902 KAR 10:140 to install on-site sewage systems. Kentucky requires certified installers — homeowners cannot install their own systems.

Effluent: The liquid leaving the septic tank after solids settle out. Its quality determines how much treatment the soil still has to perform.

Effluent Filter: A removable filter at the tank outlet that catches solids before they reach the field. It should be cleaned at every pump-out.

Karst: Limestone bedrock that dissolves over time, creating sinkholes, caves and underground channels. Much of central and western Kentucky is karst, which means wastewater can reach groundwater with far less natural filtration than ordinary soil provides.

KRS 211.350: The Kentucky statute requiring an on-site sewage disposal permit from the local health department before any system is constructed, installed or altered.

Lateral Lines: The perforated pipes distributing effluent across the absorption field. Kentucky regulations specify their sizing, spacing and depth based on soil conditions.

Local Health Department: The county-level authority that issues septic permits, conducts inspections, and enforces compliance in Kentucky. The state writes the regulations; your local health department applies them.

Percolation Rate: How quickly water moves through soil, measured in minutes per inch. It is the single biggest factor in what system a property can support and what it will cost.

Pretreatment Unit: Any device treating sewage before it reaches the absorption field — most commonly a septic tank, but also aerobic units and other engineered options under 902 KAR 10:081.

Replacement Area: Space set aside for an entirely new absorption field if the original fails. Kentucky requires 100 percent replacement area, which is why lot size matters as much as soil quality.

Riser: An extension bringing a buried tank access lid to ground level. Costs $200 to $400 and typically pays for itself within two pump-outs.

Septic Tank Service Operator: A person licensed under 902 KAR 10:170 to pump septic tanks and dispose of domestic septage. Kentucky regulates where and how septage may be disposed.

Setback: The minimum required distance between a septic component and a well, sinkhole, property line, water body, or structure. Kentucky's karst geology makes sinkhole setbacks especially important.

Site Evaluation: An assessment of soil and site conditions determining what system a property can support. Required before a Kentucky septic permit is issued.

Sludge and Scum: The solids that settle to the bottom (sludge) or float to the top (scum) in a septic tank. When these layers reach the outlet, solids escape to the field — which pumping on schedule prevents.

Soil Morphology: Evaluation of soil structure, texture and color to determine wastewater suitability. Kentucky relies on soil morphology rather than percolation testing alone in many situations.

Vertical Separation: The distance between the bottom of the absorption field and bedrock, groundwater, or a restrictive layer. In karst regions this requirement frequently forces an engineered system.