Which of the following is a key component that inspectors must include in their report?

A key component that inspectors must include in their report is the water level in the septic tank. This detail is crucial because it provides vital information about the tank's functionality and overall health of the septic system. An appropriate water level indicates that the tank is operating correctly and that there are no blockages or other issues that might hinder proper waste processing. Monitoring the water level can also help identify potential maintenance needs, such as pumping schedules or signs of failure, which are critical for maintaining the system's efficiency and preventing costly repairs or environmental hazards.

In contrast, while the condition of kitchen appliances, landscaping type, and the year the property was built may be useful in a general property evaluation, they do not provide relevant insights into the condition or operation of the septic system itself. These aspects are outside the primary focus of a septic inspection, which concentrates on the key components and functionality of the septic system to ensure it is safe and compliant with regulations.