Considering how much chlorine gets put into municipal water supplies, I'd sooner worry about chlorine poisoning than E. Coli from the water supply.
LOL, chlorine in the amounts used for water purification is nontoxic (though annoying). A gulp of even swimming pool water is harmless.
A big enough dose of ammonia or related compounds could create chloramines when the chlorine is added for disinfection.
Getting a goodly size home charcoal filter might be smart.