Just got Lawton's Friday Five email and felt compelled to post this. Also, wasn't sure if it was best in here or the "Rainwater Catchment" forum but I decided it was more about a homesteading system, as opposed to direct catchment. If mods feel otherwise, be my guest. Enjoy!
http://permaculturenews.org/2016/06/20/water-treatment-for-off-the-grid-rainwater-harvesting-systems-water-organizing-modules-woms/