Usually simple solutions are the best. That may well be the case with this cooler that features a natural filtration system. Featured by Robert O’Neill at productdose, this system employs gravity (eureka!) by pulling regular old tap water through “a dual micro-pore ceramic/activated carbon filter that removes 95% of chlorine, pesticides, heavy metals including iron, aluminum, lead and 100% cryptosporidium, giardia and sediment.” Works for me. The “filter and 2-gallon cooler go for $139 at GREENCulture. Drink it up.