The septic system inspection starts with a visual inspection. Then by running the water in the house and flushing it through the toilet ( this is a load and dye test).
In addition, the septic field and tank are located, and if possible, the tank lid is opened in order to check the fluid level and baffle.
See the diagram as an example of the measurement of the distance between the well and the septic system.
See a sample Septic Inspection Report.