If you are buying a home with a septic tank, you should consider having it inspected by a professional septic contractor. Our standard home inspection does not include this type of specialized, intrusive inspection. To properly inspect the system, the contractor will need to dig holes to access the underground parts of the system. This will include inspecting the tank, as well as the leach field.
It makes good sense to have the tank pumped at the time of this inspection. A professional septic contractor can perform both the inspection and pump the tank, killing two birds with one stone and assuring that you begin with an empty tank and a system that has been inspected. Often, you can negotiate with the seller to have them pay for the pumping.