Fort Collins Utilities adds fluoride to its drinking water based on the recommendations of the U.S. Department of Health and Human Services (HHS), Colorado Department of Public Health and Environment (CDPHE) and the American Dental Association (ADA). City Code Sec. 26-50, states that City Council is authorized by public vote to fluoridate the water supply system to levels established by CDPHE.

For more than half a century, HHS and CDPHE have recommended adding fluoride to drinking water to help prevent tooth decay. The Centers for Disease Control (CDC) recognizes the widespread adoption of community fluoridation as one of the 10 greatest public health achievements of the 20th century. According to the CDC, "For 75 years, people in the United States have been drinking water with added fluoride and enjoying the benefits of better dental health. Drinking fluoridated water keeps teeth strong and reduces cavities (also called tooth decay) by about 25% in children and adults. By preventing cavities, community water fluoridation has been shown to save money both for families and for the US health care system."

In 1967, voters approved an ordinance authorizing City Council to direct Utilities to fluoridate the drinking water provided by Fort Collins Utilities. In 2005, an ordinance was presented to Fort Collins voters regarding the removal of fluoride from drinking water. The ballot initiative was defeated, with voters choosing to continue the addition of fluoride.

In April 2015, HHS and CDPHE recommended that water treatment plants change the recommended level of fluoridation from a range of 0.7 – 1.2 milligrams per liter (mg/L) to a single value of 0.7 mg/L. In May 2015, Fort Collins Utilities lowered fluoride levels in its drinking water to match the recommended level. 

Fort Collins Utilities’ water comes from Horsetooth Reservoir and the Poudre River. The water has naturally occurring levels of fluoride typically between 0.15 and 0.20 mg/L. Fort Collins Utilities adds additional fluoride to the treated drinking water, to reach concentrations near 0.7 mg/L.

Fort Collins Utilities purchases high purity fluoride in the form of hydrofluorosilicic acid (HFS). Utilities’ standard practice and vendor contract require the HFS meet both the current American Water Works Association standard and NSF Standard 60 for products used in the treatment of drinking water.

Fort Collins Utilities' Water Treatment Plant follows stringent safety procedures when working with fluoride. The Water Treatment Plant performs multiple fluoride quality checks to ensure product safety, including:

• Requiring the fluoride supplier to provide certified laboratory results with the shipment, which are verified upon delivery. If anything in the certificate of analysis (COA) fails to meet Utilities’ established quality standards, further investigation is done before accepting the shipment.
• Testing the shipment’s physical properties to confirm that the material is correct before a driver is allowed to unload the fluoride delivery.
• Conducting a chemical analysis of the fluoride delivery sample to confirm that the fluoride’s purity matches the information provided in the vendor’s COA. If the laboratory test results raise any concerns, Utilities stops fluoridation until all concerns are addressed.

Finished drinking water is tested daily to ensure proper fluoride levels are maintained.