What characterizes an existing onsite wastewater system?

An existing onsite wastewater system is characterized by having received final construction approval. This indicates that the system has been completed, meets all necessary regulatory requirements, and is operational. Such a system has been inspected and approved by relevant authorities, confirming its compliance with health and safety regulations.

The alternative choices describe systems that do not yet meet the criteria for being classified as existing. A system under construction is still in the development phase and has not yet been finalized or approved. A system in the planning phase is even earlier, where designs are being considered but no physical work has been done. A system for temporary use only may not have the long-term compliance and approvals required for it to be considered fully operational and part of the permanent infrastructure. Therefore, only a system that has received final construction approval is considered an existing onsite wastewater system.