<P> As with some other countries, water fluoridation in the United States is a contentious issue . As of May 2000, 42 of the 50 largest U.S. cities had water fluoridation . On January 25, 1945, Grand Rapids, Michigan, became the first community in the United States to fluoridate its drinking water to prevent tooth decay . </P> <P> Fluoridation became an official policy of the U.S. Public Health Service by 1951, and by 1960 water fluoridation had become widely used in the U.S., reaching about 50 million people . By 2006, 69.2% of the U.S. population on public water systems were receiving fluoridated water, amounting to 61.5% of the total U.S. population . Near the end of 2012, 67.1% of the U.S. population were getting water from community water systems (CWS) supplying water that had fluoride at or above recommended levels . Those included the 3.5% of the population that were on CWS with naturally occurring fluoride at or above recommended levels. 74.6% of those on CWS were receiving water with fluoride at or above recommended levels . </P>

When did fluoridation of water begin in the u.s