First and foremost, an inspection is a visual survey of those easily accessible areas that an inspector can clearly see. No destructive testing or dismantling is done during the course of an inspection, hence an inspector can only tell a client exactly what was clearly in evidence at the time and date of the inspection. The inspectors eyes are not any better than the buyers, except that the inspector is trained to look for specific tell-tale signs and clues that may lead to the discovery of actual or potential defects or deficiencies.
Inspectors base their inspections on the current industry standards provided to them by their professional societies. These Standards tell what the inspector will and can do, as well as what the inspector will not do.
The Industry Standards clearly spell out specific areas in which the inspector must identify various defects and deficiencies, as well as identifying the specific systems, components and items that are being inspected. There are many excluded areas noted in the standards that the inspector does not have to report on, for example: private water and sewer systems, solar systems, security systems, etc.