Which components are typically included in an onsite wastewater system?

The correct choice identifies the essential components commonly found in an onsite wastewater system. An onsite wastewater system is designed to treat and manage household or commercial sewage where centralized sewer systems are unavailable.

The key components typically include a collection sewer that gathers wastewater from the property, septic tank(s) that provide primary treatment by separating solids from liquids and allowing for initial digestion of organic material, and a subsurface infiltration area, commonly known as a drain field or leach field. This area is crucial as it allows the treated effluent from the septic tank to safely percolate into the soil, further treating the wastewater through natural processes as it moves through the soil layers.

In contrast, the other choices include elements that do not pertain to onsite systems. A public sewer and treatment facility involves centralized waste management, which is not applicable to onsite solutions. Filtration ponds and water treatment units could be part of a larger water treatment strategy, but they are not standard components of individual onsite systems. Lastly, while a visual inspection and maintenance schedule is important for the operation of septic systems, it does not represent a structural component of the system itself, but rather an aspect of maintenance and compliance.