ours are city, county, or state of oregon inspectors. they have their own certification process, need 8 years experience, a general supervisor license [like a master electrician] and testing and interviews. i've only had one that bordered on incompetent, and was told he got his oregon insp certification because he had inspected in another state. very hard to reach one for questions anywhere, and you get whoever they send. they have to be called the day before the inspection, but they have to be there the next day, unless its really rural, then i think they may be allowed 2 days to inspect. with the slowdown, there have been a lot of inspector layoffs here so we have gotten some private inspection guys if the ahj is short handed.