[ty6853]

Not always required. I recently built a house, I did not get anything but septic inspected.

[quesera]

I'll guess that was in a rural area in the US West?

The further east and urban you go, the more rules you have to follow. This is, ultimately, sensible.

[ty6853]

Yes. Although there are a few urban areas without inspection. You could build in a burrow near a city in Alaska without even a permit, normally. When they finally outlaw me from building in the west maybe that will be my next stop...