I have always shuddered at the thought of adding a poison into my water
supply to make it 'safe', even in small amounts. In my last van, one that I
built with plans to drive to South America, I added a .5-micron Pentek
carbon block filter which supposedly is capable of removing most problem
contaminants and 'bugs'. In addition, I installed a 12V UV-light purifier. I
used it with dubious quality water in several instances over a period of 3
years without any issue. Drinking water for myself and pups. The system
required a positive-displacement pump, one with internal valves vs just an
impeller, as the filter takes a good push to flow through. Photo of the
system, as installed in a custom cabinet, Wolfsburg Edition Westy Syncro:
http://westyventures.com/utilitybox.JPG
The blue thing is the Pentek 5" filter housing, the white cylinder the 12V
UV light. The pump is to the left of the filter, 15 gallon under-seat tank.

Karl