What should I know about fluoride in my water?

FluorideFluoride, one of the most plentiful elements on earth, occurs naturally in water supplies. Water fluoridation is the addition of small amounts of fluoride to a water supply to achieve the fluoride level recommended by the Division of Drinking Water (DDW) to prevent tooth decay. California’s fluoridated drinking water act, Assembly Bill 733, became law in 1995, requiring water systems with 10,000 or more service connections to fluoridate their water supply when funding becomes available. Metropolitan Water District of Southern California (MWD) and the San Francisco Public Utilities Commission (SFPUC) have joined many of the nation’s public water suppliers in adding fluoride to its water supply. MWD began providing fluoridated water to Cal Water’s service areas in November 2007, and SFPUC has fluoridated most of its water supplies since the 1950s.

A few basic fluoride facts:

  • Community water fluoridation is endorsed by the Centers for Disease Control and Prevention and the U.S. Surgeon General. Community water fluoridation also is endorsed by numerous public health and professional organizations, including the American Medical Association, American Dental Association, American Academy of Pediatric Dentistry, DDW, and World Health Organization.
  • Most sources of drinking water naturally contains some fluoride. Community water fluoridation is the process of adjusting the naturally occurring fluoride level to the level recommended by DDW to prevent tooth decay.
  • Seventy percent of the U.S. population lives in communities served by fluoridated water supplies.
  • Fluoridation does not change the taste, odor, or appearance of your water.

Fluoridation for Cal Water Customers

Cal Water obtains some of its water from sources such as MWD and SFPUC that supplement naturally occurring fluoride to reach 0.8 milligrams per liter (mg/L) of water, the fluoride level public health organizations deem optimum for preventing tooth decay. This level is well below the limits set by DDW and the United States Environmental Protection Agency to protect public health.

The amount of fluoride in your water depends on which water system you are in:

  • Cal Water meets its customers’ needs in Westlake Village/Thousand Oaks, Torrance’s Hollywood Riviera, and on the Palos Verdes Peninsula by purchasing imported water from MWD. Because these service areas receive their entire supply from MWD, the water delivered to these customers have a fluoride level of 0.8 mg/L.
  • Because Cal Water blends the water it purchases from MWD with its local water sources in Hermosa Beach, Redondo Beach, West Torrance, Carson/South Bay, Hawthorne, East Los Angeles and Commerce, the water delivered to these customers may contain fluoride levels below 0.8 mg/L. In some areas, the fluoride level may be as low as 0.1 mg/L. Also, because these customers’ water is a combination of local groundwater and imported water from MWD, fluoride levels in the water may not be constant throughout the year. Seasonal changes in water use, operation of local wells, and other variables can affect the water supply mix and level of fluoride in the water.
  • SFPUC supplies fluoridated water to Bear Gulch, San Mateo, San Carlos, and South San Francisco at concentrations ranging from 0.8 to 1.0 mg/L. In South San Francisco and Bear Gulch, SFPUC water is blended with unfluoridated groundwater or surface water, resulting in water that has a less-than-optimal fluoride content.

Cal Water currently does not plan to fluoridate its local water sources. In accordance with Assembly Bill 733, Cal Water will fluoridate its local water supply if federal grants or outside funds become available. Cal Water monitors fluoride levels in the distribution system of all of its affected water systems to report fluoride levels to DDW. Monitoring data will be available on the DDW web site.

Dietary Fluoride Supplements

According to DDW, children’s fluoride supplements, whether pills or drops, should be discontinued when the drinking water is fluoridated. For customers who receive water from a combination of local water sources and imported MWD or SFPUC water, the continued use of topical fluoride treatments by the child’s dentist may still be recommended. Please consult with your child’s dentist regarding proper dental care. More Information Additional information is available for certain districts:

For the most up-to-date fluoridation schedule or for more information on fluoridation, contact us.