Since the 1950s, many states and communities have mandated or recommended the fluoridation of their public water systems. According to an article released by the Center for Disease Control and Prevention (CDC) in February 2002, nearly two thirds of the nation's population (approximately 162 million people) is served fluoridated water. A 2001 survey by the National Center for Fluoridation Policy & Research revealed that fluoridated water is provided (or recently approved and soon to be provided) in 46 of the 50 largest U.S. cities. A similar survey performed by the San Francisco Public Utilities Commission (SFPUC) in 2000 indicated that fluoridated water is provided (or recently approved and soon to be provided) in 7 of the 10 largest cities in California. Large California cities that started fluoridating their supply or adopted resolutions to convert to a fluoridated supply in 1999-2000 include Los Angeles, Sacramento, San Diego and Modesto.

See Appendix 6 of the SFPUC Fluoridation Feasibility Study for (1) more detailed statistics on the fluoridation practices of drinking water utilities in the U.S. and California, and (2) a summary of the November 2000 election results of nationwide fluoridation ballot initiatives.