Fluoride occurs naturally in water supplies and historically was regulated as a contaminant as it is a very common element and at elevated levels over a long period of time can result in a condition known as fluorosis. There are two types – dental fluorosis and skeletal fluorosis.

The California maximum contaminant level (MCL) for naturally occurring fluoride is 2.0 milligrams per liter (mg/L), or 2.0 parts per million (ppm). During the latter half of the 20th century, benefits of low fluoride at concentrations much lower than the MCL were determined to be useful in reducing dental cavities and California began to develop rules to promote the addition of fluoride to drinking water in carefully controlled and monitored levels. 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.

Currently, six of Golden State Water’s systems fluoridate their drinking water. In addition, several of our systems purchase water from a wholesale agency or city that fluoridates its water. As more state and federal funding becomes available for fluoridation, Golden State Water will implement fluoridation in our other large systems that have naturally low fluoride levels in their source waters.

Fluoride in drinking water is unique in that there is an historical MCL established to reduce exposure to elevated levels of fluoride and a recent regulation requiring the addition of fluoride in systems where the naturally occurring levels are very low in an effort to reduce dental cavities.

Golden State Water routinely monitors and tests for more than 230 contaminants, including fluoride, to ensure the water we deliver to customers meets all state and federal drinking water standards. Golden State Water makes water quality information available via annual Consumer Confidence Reports (CCR).

Water quality test results are directly submitted by the State certified laboratory to the State of California’s Division of Drinking Water (DDW) and recorded on the State’s website for full transparency. Click here to view test results on the DDW website.

As your water provider, we continually invest in water infrastructure, treatment and testing and take great pride in providing you with high quality, reliable water.

Frequently Asked Questions

Q:  Has fluoride been found in my drinking water?
A: In 2017, fluoride was detected in treated drinking water in most of our 37 water systems. The levels of fluoride detected were below the current MCL. Fluoride levels in many of our systems are near the optimal fluoride level of 0.7 mg/L recommended by the Centers for Disease Control and Prevention (CDC) for the prevention of tooth decay.

The water served to customers in each of Golden State Water’s water systems meets all state and federal drinking water standards for safety, including the fluoride MCL. Click here to see the most recent results for fluoride levels detected in our treated drinking water.

Resources for Additional Information

State Water Resources Control Board