Fluoride is a naturally-occurring element found in soil and water. We add fluoride to Seattle drinking water to an optimal level for the prevention of tooth decay.
Fluoridation of Seattle’s water began in 1970 after a referendum vote in 1968 directed the City to fluoridate the drinking water. Seattle Public Utilities sells water to 21 wholesale customers (cities and water districts) generally located around Lake Washington. Those wholesale customers also receive fluoridated water. Nationwide, over 70 percent of people on public water supplies receive fluoridated water.
Public health, dental, and medical authorities overwhelmingly support drinking water fluoridation as safe and effective. Our local, state, and national public health agencies all strongly support fluoridation. The U.S. Centers for Disease Control have proclaimed drinking water fluoridation as one of the 10 great public health achievements of the 20th century. There is also strong support for water fluoridation by other prominent health organizations, including the American Dental Association, American Medical Association, and the American Public Health Association.
Historically, Seattle Public Utilities targeted a fluoride level of 1.0 part per million, which is the same as one milligram per liter (mg/L). This level is at the middle of the range required by the Washington State Department of Health, which is 0.8 to 1.3 parts per million. In January of 2011, the U.S. Department of Health and Human Services and the U.S. Environmental Protection Agency proposed a recommended level of fluoride in drinking water of 0.7 parts per million. The updated recommendation has yet to be finalized, but we expect that to happen sometime in 2012. Seattle Public Utilities has consulted with our local health department (Public Health – Seattle & King County) and the state Department of Health on this issue. As an interim approach, Seattle Public Utilities has adjusted the fluoride level to 0.8 parts per million, closer to the proposed recommendation, but within the existing state range.