A septic tank is an underground wastewater treatment system in areas where centralized sewer systems are not available. It is to collect, store, and treat sewage from households or buildings. Here are some key terms related to quality septic tanks:

1. Septic Tank: A septictank is a large, watertight container typically made of concrete, fiberglass, or plastic. It receives wastewater from toilets, sinks, showers, and other plumbing fixtures. The tank separates solids from liquids, allowing bacterial action to break down organic matter.
2. Capacity: The capacity of a tank refers to its volume, usually measured in gallons or liters. It determines the amount of wastewater the tank can hold. The size of the tank should be appropriate for the anticipated wastewater flow to prevent overloading and ensure effective treatment.
3. Construction Materials: Septic tanks are commonly made of different materials, each with its advantages. Concrete tanks are durable and long-lasting, but they can be heavy and require proper sealing.
4. Inlet and Outlet: A septic tank has an inlet pipe through which wastewater enters the tank and an outlet pipe through which treated effluent exits the tank. The placement and design of these pipes should ensure proper flow and prevent the escape of solids.
5. Baffles: Baffles are partitions or barriers inside the septic tank that help control the flow of wastewater. 
6.  Proper Ventilation: Septic tanks require proper ventilation to allow gases produced during the decomposition of waste to escape.
7. Regular Maintenance: This includes periodic pumping of accumulated solids, inspecting and repairing any damage or leaks, and following recommended maintenance schedules provided by manufacturers or local regulations.