Freedom made a few comments above that should be taken very seriously about the amount of water he used, and the fact that what he had available wasn’t always considered safe (e.g. that they had water to flush toilets, but it wasn’t considered safe for drinking).
About three years ago he posted the following, and it grew into a nice thread for a while. It’s well worth reviewing.
We built the same system from the same plans a number of years ago ourselves, and highly recommend it. We’ve made a few upgrades (better spigot, put it on a rolling mechanic’s stool in order to keep it out of the way but have it easily accessible for refilling, etc.), but it’s still the same basic 2-bucket system. We also added two additional filters to increase water flow (and filter replacement time). As the water level gets lower in the top bucket, the pressure through the filters naturally reduces, as well as the fact that only part of the filter still has water around it to feed water down into the lower bucket. And the flow rate decreases as the water level goes down.
This is ALL we drink and cook with. We run tap water through it, and the taste rivals or beats any bottled water you’ll find anywhere. Plus, the Berkey Black filters (our preference) filter about 99.999% of virtually all chemicals, viruses, bacteria, etc. At 6000 gallons per pair and a little over $100 to build a 2-filter system, that’s only about $.02 per GALLON of water. Compare that to any bottled water. As noted in comments I made at the end of Freedom’s thread above, I talked with New Millenium Concepts (the actual manufacturer of the filters), and they said that there is no time limit on the filters – ONLY gallons, with full safety. (We’ve also opted to spend extra on their fluoride/arsenic filters – those hang down in the top of the lower bucket, attached to the bottoms of the Berkey Black filters.)
We keep five 55 gallon barrels (275 gal. total) connected to a rain water collection system filled at all times, periodically draining and then refilling (a couple inches of rain or so will refill all five). Because we don’t get the same winters as MountainBiker, Brulen, or Whirlibird, for example, we don’t have to worry about the barrels freezing up solid. So we’ve ALWAYS got plenty of water that we can run through the filter, if needed during a long term water outage.
In the actual plans (bottom link in Freedom’s first post in the thread) is a link to THE Berkey company (New Millenium Concepts). I strongly recommend purchase through them, not Amazon or other sources – Berkey won’t honor warranties if not purchased through them or their authorized distributors (long story, but good reasons).