I've found that places exempt from building codes are much more common than places exempt from health code. Be sure to read up on local plumbing, waste water, s

I've found that places exempt from building codes are much more common than places exempt from health code. Be sure to read up on local plumbing, waste water, septic, etc. code. They will often dictate things like how big the septic system needs to be, how big pipes need to be etc. Generally good rules to follow if you want such a system. If you want a legal outhouse or composting toilet and/or grey water setup, there are very few places in the US which allow it so be sure to read up first.