Fluoride is a naturally occurring mineral in many water supplies. Water fluoridation is the controlled addition of fluoride to a public water supply for the purpose of decreasing the risk of tooth decay.

While small amounts of fluoride are found naturally in lakes, rivers, and streams, NTMWD adds fluoride to the water system to prevent tooth decay – a process that is endorsed by the American Dental Association, the American Medical Association, the Center for Disease Control, the U.S. Public Health Service and the World Health Organization.

Quick Facts

  • The source water treated by NTMWD has an average fluoride concentration of 0.3 ppm (parts per million).
  • NTMWD adjusts fluoride levels in treated water to 0.7 ppm per the Health and Human Services recommendations.
  • The range of fluoride levels in NTMWD water is consistently well below the maximum level of 4.0 ppm set by the US EPA.

The U.S. Environmental Protection Agency (USEPA) set the maximum contaminant level goals (MCGL) level for fluoride at 4.0 mg/L or 4.0 parts per million (ppm). To learn more about water quality, view our reports or download our fact sheet below. NTMWD monthly water quality reports provide  fluoride levels calculated on a monthly average.

Download NTMWD Fluoride Fact Sheet 

View Water Quality Reports



NTMWD approved the increased addition of fluoride in the water system in 1981 at the request of its Member Cities and after concurrence by the NTMWD Board of Directors. This was implemented in 1982 and has been ongoing ever since.

More than 70 years of scientific research has consistently shown that an optimal level of fluoride in community water is safe and effective in preventing tooth decay by at least 25% in both children and adults. Simply by drinking water, Americans can benefit from fluoride’s cavity protection whether they are at home, work or school. The Centers for Disease Control and Prevention named community water fluoridation one of 10 great public health achievements of the 20th century.

In 1974, Congress passed the Safe Drinking Water Act, which requires the U.S. Environmental Protection Agency (USEPA) to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur. These non-enforceable health goals, based solely on possible health risks and exposure over a lifetime with an adequate margin of safety, are called maximum contaminant level goals (MCLG). Contaminants are any physical, chemical, biological, or radiological substance or matter in water. The USEPA has set the level of protection based on the best available science to prevent potential health issues. The MCLG level for fluoride is 4.0 mg/L or 4.0 parts per million (ppm).