In Maine you do not have to be licensed or insured to perform general property inspections. In fact Maine has no guidelines for home inspectors which means you can have zero knowledge about buildings and their components but be a home inspector. You do have to be licensed to perform radon testing of any kind. No license or insurance is needed to perform septic inspections either, however if you choose to take and pass certain courses you can be put on an approved list of inspectors with the state of Maine. You the consumer needs to decide what level of competence and security you want behind your inspections. I recommend doing your homework before deciding who to hire and trust with this very important decision.