The worse case here in recent times was at Walkerton Ont. Canada. Heavy rains and spring run off ran contaminated water into the towns wells. The guys running the system were either asleep or drunk at the wheel and most of the drinking water entered to the system without any chlorination.
By the time anyone realised there was a problem several hundred were sick and several died. The media were quick to pounce on agriculture but the inquirery found no links at all - the public still thinks so anyway. The result is some of the toughest water standards anywhere in NA. Truly Orwellian stuff.
