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Fluoridation by Public Water Systems

Fluoridation by Public Water Systems

Is My Water Supply Fluoridated?

Please Note:

  • Detailed information on your drinking water quality (including fluoride levels) is available in the annual Consumer Confidence Report (CCR) issued by your water provider.
  • Contact your water system for a copy of the current CCR or check your water system's webpage

Background Information on Fluoridation Data

The Division of Drinking Water (DDW) receives water system fluoride monitoring results from fluoridating water systems each month. Naturally-fluoridated water systems and systems that purchase fluoridated water are not required to monitor and report the fluoride levels in their water distribution system, except on a voluntary basis.

DDW maintains a table showing data for 2013 submitted by public water systems in California that fluoridate their drinking water supplies, are naturally fluoridated, or receive purchased fluoridated water. The table lists the average monthly fluoride levels in those systems, if the data are available. Ranges of fluoride levels are provided where monthly data are not available. Fluoridation level information is also available in the annual CCR provided to you each year by your public water system. Find and contact your public water system for this information.

2013 Fluoridation Data

Additional Historic Fluoridation Data

Fluoridation - April 2015 Revision to Optimal Fluoride Level

The U.S. Department of Health and Human Services Agency (HHS) is recommending that water systems practicing fluoridation adjust their fluoride content to 0.7 mg/L (parts per million), as opposed to the previous temperature-dependent optimal levels ranging from 0.7 mg/L to 1.2 mg/L. There is no change regarding federal health officials' strong and long-standing support regarding the value of fluoridation of drinking water.

Detailed information on the basis for this change is available via the Centers for Disease Control and Prevention's (CDC's) website. The change in the optimal level is a result of recent scientific evidence in four areas on the subject:

  1. The effectiveness of fluoridation on dental caries prevention and control for all age groups.
  2. The availability of fluoride through other sources
  3. Trends in the prevalence and severity of dental fluorosis
  4. Fluid intake by children across various ambient air temperatures.

This optimal target goal is aimed at providing the benefits of fluoridation while minimizing the chance that children develop dental fluorosis, a typically mild condition that causes a discoloration of teeth.

To reflect CDC’s recommendation, DDW will be consulting with public water systems practicing fluoridation regarding amendments to their individual public water supply permits to reference the CDC's recommended optimal level of 0.7 mg/L. The recommended optimal level of 0.7 mg/L currently corresponds with the existing California Water Fluoridation Standards control range of 0.6 mg/L to 1.2 mg/L. Public water systems are advised of the following:

  • Public water systems practicing fluoridation are advised that they may immediately implement the CDC’s recommended optimal level of 0.7 mg/L and control range of 0.6 ppm to 1.2 ppm.
  • DDW District Offices will issue a letter to each public water system practicing fluoridation by the end of May 2015 and initiate the water supply permit amendment process soon after.
  • DDW will be developing amendments to the California Code of Regulations to incorporate the new CDC recommendation.

Water system practicing fluoridation may contact the local DDW District Office with questions regarding the addition of fluoride to the water supply or the maintenance of optimum fluoride concentrations in the water delivered to customers.

Tooth decay is the number one chronic condition for children. It may result in pain, poor nutrition, and dysfunctional speech, as well as a lack of concentration, poor appearance, low self-esteem and absenteeism. Optimally fluoridated water is the single most cost-effective strategy that a community can take to improve the oral health of its residents. Studies consistently show that water fluoridation reduces tooth decay by 20 to 40 percent. The recommendations of HHS resulted from an updated review of the various current sources of fluoride, including water fluoridation. Providing the optimal level of fluoride protects the dental health of people of all ages, not just children.


Fluoride is one of the most plentiful elements on earth, and occurs naturally in water supplies throughout California and elsewhere. When fluoride is present in drinking water at optimal levels, it has been shown to promote oral health by preventing tooth decay. Water systems are considered naturally fluoridated when the natural level of fluoride is greater than 0.7 parts per million (ppm). When a water system adjusts the level of fluoride to 0.7-1.2 ppm, it is referred to as water fluoridation. Today, about 67 percent of the U.S. population on public water supplies has access to fluoridated water. Additional information on water fluoridation and oral health is available at the following locations:

Fluoridation and Infant Formula

Concerns have been raised about the use of fluoridated drinking water in infant formula. For more information on this topic, click on the links below.

Fluoridation Management

The fluoridation of public water systems in California by two of its organizations:

  • DDW provides technical and engineering expertise to public water systems for permitting and operating fluoridation systems. DDW is the regulatory agency and responsible for assuring fluoridation systems are optimally fluoridating the water supplies to provide dental health benefits.
  • The Office of Oral Health (OOH) within the Chronic Disease Control Branch, provides scientific, technical, and health related expertise to communities interested in fluoridating their drinking water supplies. OOH is also responsible for securing funds to purchase and install fluoridation equipment for public water systems.

Fluoridation Monitoring and Reporting

DDW is responsible for regulating the activities of fluoridating public water systems in California. This responsibility includes assuring water fluoridation is conducted in a safe and effective manner. Public water systems must obtain a permit from DDW to fluoridate their drinking water supplies and must monitor the fluoride levels in their water system on a daily basis. The operational and monitoring information is also reported to DDW. For copies of the reporting requirements and reporting forms, click on the links below.

Reporting Requirements and Reporting Forms

Required Reporting Where there are two, choose the correct report form to use
Monthly Distribution Monitoring Monthly Distribution Monitoring - Single Fluoridation Treatment System
Monthly Distribution Monitoring - Two or more Fluoridation Treatment Systems
Year-to-Date Distribution Summary Year-to-Date Distribution - All Fluoridation Treatment Systems
Monthly Treatment Summary Monthly Treatment Monitoring
Monthly Treatment Monitoring - SATURATOR Systems only
Yearly Treatment Summary Yearly Treatment Summary Report - All Fluoridation Treatment Systems
Optimal Fluoride Control Range Calculation (Done Annually) Optimal Fluoride Control Range Worksheet
Annual Cost Summary Annual Cost Summary Report - All Fluoridation Treatment Systems
Voluntary Fluoridation (Only for systems that purchase fluoridated water but do not supplement with additional fluoride) Voluntary Distribution Monthly Monitoring Report
Voluntary Year-To-Date Distribution Monitoring Report


References for Fluoridation Treatment Facility Design

Three references often used for design purposes are from the Centers for Disease Control and Prevention (CDC) and the American Water Works Association (AWWA):

  1. Engineering and Administrative Recommendations for Water Fluoridation, 1995. MMWR, September 29, 1995;44(RR-13):1-40. A PDF file is also available.
  2. Reeve, T.G., Water Fluoridation, A Manual for Engineers and Technicians, Atlanta, US Department of Health and Human Services, Public Health Service, CDC, 1986.
  3. Water Fluoridation Principals and Practices, William C. Lauer, Fredrick Rubel, Jr., 5th ed., (AWWA manual M4).

Contact Information

For detailed information on your drinking water supply, please contact your local water supplier. A contact number for your water supplier should be included on your water bill.

For further information concerning

  • fluoride and oral health, please contact OOH at (916) 552-9947.
  • fluoridation, please contact your DDW District Office

*NOTE: Links to non-Government organizations are provided solely as a service to our users. Links do not constitute an endorsement of any organization by DDW or the State of California, and none should be inferred. DDW is not responsible for the content of the individual organization Web pages found at this link.


(Updated 5/7/15)