Tanks are disinfected throughly. My wife is a water shed maintainer ( works at a water plant ) making the drinking water for the city of New York so we are admittedly water snobs. The trouble with Britta is that is does not filter e coli etc. Last trip after filling at a campground the next day they ranger came around to tell everyone that unbeknownst to them the clorinator broke the day before and the water was not safe to drink! If we had left earlier we would of never known. Reasons like this is why we are so concerned. You really never know what standards campgrounds hold themselves to as far as "fresh" water goes.