Inspectors must ascertain the designed system size for which purpose?

The correct answer focuses on the necessity of ensuring compliance with operation permits. Inspectors need to ascertain the designed system size because it plays a critical role in determining whether the septic system can effectively handle the wastewater generated by the property while adhering to local health and safety regulations. Every permitted septic system has specifications that are directly tied to its intended use, and if the size is not appropriate for the volume of effluent generated, it may lead to system failures or environmental hazards.

By confirming that the system size matches the designed specifications laid out in the operation permits, inspectors ensure that the system functions correctly and does not pose risks to public health or the environment. Inspectors protect both the system's integrity and the surrounding ecosystem by validating that the installation is compliant with established standards, which ultimately safeguards community health.