Two to three hours for a standard residential system including the pump-out. Add time if the lid is buried, if the field has to be probed, or if a camera run is needed to settle a question about the line.
Why the tank gets pumped first
You cannot inspect a full tank
The parts that fail live below the liquid line. Inlet and outlet baffles, the outlet tee, the effluent filter seat and any cracking in the walls are all underwater in a tank at normal level. An inspection that skips the pump-out is an inspection of a lid.
So a proper inspection is usually booked together with septic tank pumping: the tank is emptied, the interior is photographed, then the system is run to check that effluent leaves and does not come back. That sequence is what lets a report say something definite rather than something hedged.
Where the line between tank and field is the question, a dye test traces where water actually goes, and a camera inspection shows roots, bellies and breaks in the run itself.
Before inspecting
Tank pumped
Of every component
Photographs
Within 24 hours
Report
