We only inspect components that are visible and readily accessible. Sewage drain lines and septic systems are typically located below ground and are typically considered out of the scope of a home inspection. We highly recommend you contact a qualified plumbing contractor and/or a septic inspector (when applicable) and have these systems evaluated. These systems, like all others, can experience problems or fail, and having them inspected is always a good idea during your due diligence period prior to purchase.