So, maybe a big pressure tank but no bladder or keep bladder empty. Would need to be tied into city water to keep full. To get out, I would need to use a pump to pump from tank into rest of house, probably with an rv pump. I suppose with some creative plumbing I could do something like this. Now, I just need to find a tank that can be presurized to 70psi and hold about 150 gallons or so.