http://articles.mercola.com/sites/articles/archive/2001/01/07/chlorinated-water.aspxWritten by Joseph G. Hattersley , May 1999 Federal regulations require chlorine treatment of the water supplied to urban/suburban America from surface sources such as lakes, reservoirs and rivers. That constitutes about 75 percent of water that AmericansenCommunityServer 2008.5 SP1 (Build: 31106.3070)