If you are buying a home with a septic system, a well system, or both, a thorough inspection of these systems is a key part of a good inspection. These inspections are best undertaken concurrently with the home inspection.
A home inspector trained in these systems will typically add about 1 1/2 hours extra to the 4 hour timeframe of the home inspection.
Septic Systems
A septic system should be inspected to verify that all sewer drains in the home feed the septic system. The proper location of the septic system should be verified to ensure that the well water is not being contaminated, and that the system is properly located away from the house and property lines. Verification that the system is accepting fluids properly is also important. Other details include appropriate sizing of the drain field, integrity of the septic tank, its lid and baffle, and proper design of a sewage lift station where applicable. It is best to have the septic tank pumped during the septic system inspection, as more information can be detailed, such as proper design of the baffle proper grade on inlet and outlet piping in the tank, sludge build-up relative to the baffle outlet, scum layer thickness and contents, grey water depth and color, and fluid back-flow from the drainage pipes.
Understanding how to maintain a properly use a septic system is important. Your inspector should take time to explain this to you.
Well Systems
A well system should be inspected for proper electrical power and wiring, proper electrical grounding, water flow-rate, high and low pressure settings, integrity of the bladder/expansion tank, and operation of shut-off valves. Water quality is also important, particularly concerning bacterial contamination, contamination from pesticides, herbicides, fertilizers, and salt content. Your inspector should be well-trained and knowledgeable in these areas.