I guess it would be alright to drink it if you don't know that
it's unsafe to do so. 
Saccharin was an approved sweetener till it was discovered to
cause cancer and subsequently banned. 
To me it's the lesser of two evils, if the
government don't chlorinated our water, chances for microbial
diseases will increase. So they chose chlorination as the lesser
evil. 
Trihalomethanes and Colorectal Cancer
Studies conducted at HIEHS have shown that administration of
certain trihalomethanes, by-products of water chlorination, and
several brominated chemicals cause colorectal cancer in
experimental animals. Epidemiologic studies now suggest a
link between the consumption of chlorinated water and increased
human risk for colorectal cancer.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1567194/?page=1