Contaminants vary for each water supply, and from region to region. A May 2002 study (by the U.S. Geological Survey)found chemicals in riverewater that cam from drugs, detergents, disinfectants, insect repellents, plastics, and personal care products, including 33 suspected hormone disruptors.
At the national level, 1998 US E.P.A. study reported in 1998 that 6% of the country's water systems had violated health standards, for at least one of 90 regulated contaminants that year.
Canadian water quality is determined by federal standards (Environment Canada). And Candian water naturally has a wide range of dissolved solids (Chart). Drinking Water is managed under a separate set of federal standards by Health Canada and Canadian drinking water has similar sets of impurities (levels may vary)
The US EPA (Environmental Protection Agency has created a list of contaminants, their health impacts and their MCLs