Dreaming of just big enough

I have read with great interest all the incredible projects in this Permies community. Absolutely inspiring!
I want my own homestead/small world/retirement and sustenance plan.
Many farmland properties here in southern Ohio are lightly hilly, have some woodland adjoining, and were contoured to face a bit more south than anything.

So here is the question - I am unfamiliar with building code and all that. What specifically should I do to get started building my small house? No doubt I can build something safe and green on my own resources, but code enforcement must be satisfied in order to call something my main residence for the long term. No "messing about" until there is a legally occupiable residence.

Local code enforces the state code, so basically it has to match Ohio building code - then its good.

Does anyone have experience navigating the build of a home with composting toilet, local gray water treatment, and a wood stove/furnace? If I can get that up and going, experimenting is on me later, as they leave well enough alone around here.

I do have construction background and far too much energy, so it is going to be me doing the grunting and cussing to get this done.

Any help appreciated, yall.

If you don't want to talk to the building code people in person or if they wont take time to talk to you, you can check out their website online. That is what I did. Be sure to check out any minimum size requirement if you are building small. You should be able to find the answers to most questions there. Make friends with someone in the area who has recently built. Most people want to share their adventures in building especially rural people.

I would suggest looking into local architects. There are many who specialize in eco-friendly buildings and they know the ins and outs of the local and state codes. Paying for a good consult, or even plans, that you know have been vetted and inspected, will save you both time and money down the line.

OK. Thanks for the input. I will pluck up my bravery and talk with some utilities and building code folks.

Also, anyone know of a college with renewable energy program including practical application?
Something like this may be a useful resource for these questions?

Thank you all
Any and all help appreciated - and I will post whatever comes of this (eventually)

Talk to the inspector. I looked on line for septic specs and then talked to the inspector and she said the website was wrong and a bigger system was needed.

We have some fun rules like you can legally have an outhouse, as long as it has a holding tank and lateral lines...so an outhouse with a septic system. Really? I can do a composting toilet but have to have septic for any other water used, including if I bring in rain water.

Strange stuff but know it before they make you rip it out.