I have been looking into something like this for quite awhile, and this is the plan I have come up with, and hope to one day realize. I am wanting to
purchase 20-30 acres, with the land being semi-hilly. I would personally/secretly build an underground bunker-style system first, into the top of a
hill, to minimize water seepage. I would make it very roomy, with an excellent support system in place and any type of bilge pumps, etc for any water
that does make it into the structure. I would re-cover the entire structure with sod, then build a legally conforming, very small house onto the top
of it, with no indication of the structure underneath. After final completion of the conforming structure, and all inspections/whatnot is completed,
then install the access door leading to the subterranian rsidence in the floor of one of the closets, able to be hidden anytime as needed. Also, you
can install the "skylight tubes" into the above-ground house, but with the tubes running inside existing walls, so that they are unseen in the above
house, but perform their functions for the below residence. The water system will then be connected to the below residence and set on a tankless
heating system fed with rainwater from the gutters (filtered of course), and could also run a T into the house to connect it to the main water supply,
in case of long periods of no rain. All Solar Panels can go on the roof of the above house, no one will ever have a clue as to what exists under that
little frame house that sits on the hill. I will not be completely off the grid, but pretty close to it. No need to heat/cool the small house above,
its mainly just for show anyhow.
A second variation would be to build the above, but cinder block a small portion of the below residence off to look like a typical basement, and
show it in the plans of the small house. After inspections are complete, cut a door into the cinder block walls to access the rest of the subterranian
residence. Voila! My underground, legally conforming, 90% off-the-grid residence, that I didn't have to fight red tape to achieve.
just my idea........
[edit on 4-12-2008 by theQuest]