Our Team Canada adventure team has used the Zerowater for several years.  Spending a week each year at a wilderness outpost camp in Northern Ontario requires us to use lake water for our H2O needs.  While the water coming out of the lake is very brackish (tea-colored), once we run it thru the Zerowater pitcher, it comes out totally clear.  We have never experienced any ill effects from drinking and cooking with that filtered water.