There are some folks near us who are using a "military" filtration system. The military bids on filtration systems. AquaPure water systems is probably the best known. The small stuff is in your local WalMart. You can contact them directly for the big stuff. They can do any size filtration system. My biggest concern would be replacement filters/parts. The military types of systems are probably the best to look at just because they are expected to work in times of great duress.
Offered by John.