Tricky inspection question

Hello all. I have a question about a project I am planning to convert a non-residential building into a residential. This is out in the mountains of North Carolina where people’s adherence to permitting and inspection regulations are shaky at best. Basically the locals don’t usually get permits if they can avoid it. The building was built 20 years ago (with no permits) as an office-type space next to an old cabin in the country. It is a well-made building and has electricital system, water lines (not currently connected to the supply) and the necessary rooms were framed when it was built. Basically two rooms originally built as storage areas would work as a bedroom and bathroom. So all I need to do work-wise to turn it into a cabin is plumb the bathroom and kitchen and hook it up to septic. My dad is a master plumber, so that’s no sweat.

My issue is the septic. The septic system on the property (from before I bought it) was not permitted. It’s only about five years old and can handle the additional capacity (according to the guy who built it), but a permit was not taken out. I want to hook my building into the system. I also want my structure to be permitted as a residence so it’s above board and i can sell it as a residence if I want to. My question is, when the inspector comes to look over my dad’s plumbing, is he going to stop inspecting at the point where the building’s drain line meets the line to the septic, or is he going to trace is all the way to the septic tank and start asking questions? I don’t want to replace a perfectly good septic system just because the guy before me didn’t get a permit for it. I know there are no guarantees about what any inspector would do, but what is typically done? Thanks in advance for the advice!

The vast majority of people on this forum or not code compliance inspectors. There are a few, and they might chime in but your questions should be aimed at the local authority having jurisdiction. (Code inspector) especially if your goal is to bring the building into code compliance to avoid headaches selling it down the road.

Hope that is of some help to you.