Jim–
Instead of water barrels a previous contributor mentioned in fashioning a water supply setup, surplused water heaters can be used.
(1) They usually are sound, only have failed heater systems–just need flushing;
(2) They are already fitted with correct interior piping and external pipe fittings;
(3) If you can get one tank in the sun (make an insulated box–plans are everywhere), presto, a pre-heater for the hot water tank and a savings on your heating bill;
(4) If you can get these tanks elevated, you should be able to get a little bit of extra pressure for draining off needed water from the lowest one–or, put a pressure tank first in line;
(5) The valve between the street supply and the first tank in the lineup is called a check valve.
And those barrels? Fill ’em up and use that water for flushing. – Bob
JWR Replies: Keep in mind that water heaters have thin walls. So anything that you construct with used water heaters should be assumed to rust out and leak at any time. Position them accordingly, to avoid having a flooded house!