How many experimental systems must be installed before unconditional approval is granted?

Unconditional approval for septic systems is typically granted after a specified number of experimental systems have been installed and evaluated. The requirement of ten systems indicates that a sufficient amount of data and performance observations can be gathered to assess the reliability and efficacy of the system. This number is likely determined based on both industry standards and regulatory guidelines to ensure that a wide variety of conditions and potential issues are considered.

Installing ten systems allows installers and regulators to analyze various factors such as soil types, environmental conditions, and maintenance requirements, providing a comprehensive understanding of how the system performs in real-world applications. This data helps in ensuring that the systems are safe, effective, and appropriate for use in different scenarios, which is critical for the protection of public health and the environment. Thus, ten experimental systems is the established threshold before moving forward with granting unconditional approval.