Not that we get a lot of water purity problems here in California, but this would have been REALLY useful for the people who had to suffer and wait 5 days for water when Hurricane Katrina hit New Orleans. In fact, emergency hurricane situations and the persistent condition of dirty and diseased water in third-world areas is what inspired the creator of this system.
Anyway this is an awesome invention. The simplicity of use, capacity of use, and ability to filter any waterbourne virus or bacteria is really amazing. Just probably won't desalinate or remove chemicals.
The maker sets up options to purchase and send these things to donate to disaster victims as well.