Construction permission is different from state to state. At least in Bavaria, water and waste water can be independent from the grid. Electricity is funny, because off grid is allowed, you still seem to have to pay taxes and grid fees (I could be wrong here, never dug to deep here). Having a road, yeah, you want to get to your house, don't you?

Cabins and such need a permit, or have to grandfathered. There is even a way to treat them as a "non-permanent" building.