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Fluoride in MWRA Drinking Water

Massachusetts Water Resources Authority

MWRA has completed construction and testing of the fluoride system upgrade. Fluoride feed was restarted on Monday June 12th and fluoridated water will be arriving at customer’s homes throughout the next week or so depending on the distance from the water treatment plant and local pipe network configuration.

Temporary Fluoride Shutdown

As part of a project to replace portions of the fluoride feed piping and equipment at the Carroll Water Treatment Plant serving MetroWest and metro Boston communities, MWRA will need to shut down the fluoride feed for a few months starting in late February. While fluoridation is important for dental health, health officials indicate that this short-term shutdown does not require any special additional action by consumers.

  • Water customers do not need to take any special action.
  • This planned and temporary shutdown will allow for the maintenance of our water treatment system that adds fluoride and adjusts it to the best levels for good oral health.
  • The shutdown is expected to last around 90 days or less. Check back on this page for project and schedule updates.

The temporary fluoride shutdown is a good reminder of everything that contributes to good dental health:

  • There are currently no changes needed from regularly recommended good oral health practices because of the short-term nature of this planned shutdown.

In addition to regularly drinking tap water with fluoride when it’s available, some of the tips for good oral health include:

  • Brushing teeth with fluoride toothpaste. Aim for 2-minutes, twice a day, using a soft toothbrush. 
  • Floss (clean between teeth). Aim for at least once a day.
  • Get a “check-up” with an oral healthcare professional, at least once per year or as directed by your healthcare professional.
    • For infants, schedule the first dental visit no later than the first birthday.
    • For children and adolescents, ask about protective teeth coatings called dental sealants at their “check-up”.
    • When seeing your medical or oral healthcare professional, ask about topical fluoride varnish (a brush-on protective mixture) that can be applied to children’s teeth up to every 3 months - starting from the time the first tooth comes into the mouth (about 6 months old) and continuing until at least age 5.
  • Learn more about recommended good oral health practices specific for all ages at the Centers for Disease Control and Prevention website: Basics of Oral Health.
  • General information about the oral health benefits of fluoride in drinking water is available at the Office of Oral Health  website at the Massachusetts Department of Public Health. 
  • On the Community Water Fluoridation Status webpage, users can also find information on oral health disease prevention, information for healthcare providers, and a feature to look-up any city or town’s water fluoridation status, outside of this temporary shutdown period.    

The MWRA is a proud supplier of drinking water with fluoride for over 40 years! We look forward to completing our fluoride system maintenance and continuing to provide our more than 2 million customers in the Boston metro area with this important benefit to their good oral health.

Additional Information on the Project:
MWRA is about to replace large portions of the almost 20-year-old chemical feed system for fluoride at the Carroll Water Treatment Plant. To safely and efficiently perform the work, it will be necessary to shut down the fluoride feed system for a few months. MWRA has been providing fluoridated water to the region since the 1970s, and due to its importance in protecting dental health, consulted with the Department of Public Health (DPH) Oral Health Office and the Massachusetts Department of Environmental Protection (MassDEP), both of whom approved the fluoride shutdown.

To do the work safely and to reduce the risk of operational problems, MWRA plans on using the remaining fluoride in the storage tanks, draining the equipment and piping, and handing the empty system over to the contractor, which will then be able to replace all the components safely. When the work is completed, all of the new system can be safely tested and adjusted with water before reintroducing chemical, decreasing the risk of unexpected issues and reducing personnel safety risks.

The current schedule is for the work to begin in late February, with the fluoridation system being off-line of approximately three months. Check back on this page for project and schedule updates.

If you have questions about the fluoridation project, contact us at (617) 242-5323 or

MWRA maintains a target fluoride level of 0.7 ppm, as recommended by the CDC and US HHS, and EPA to reduce tooth decay. MWRA has added fluoride since the 1970s, and continuously monitors the levels.  MWRA is aware that a number of people across the country sometimes raise questions about fluoride in drinking water. MWRA intends to keep an open-minded view, keep abreast of all current scientific research on the topic and pay close attention to competing viewpoints.

Even in light of recent news reports concerning fluoride, the American Academy of Pediatrics continues to recommend that children drink fluoridated tap water. The American Dental Association also states that it remains committed to fluoridation of public water supplies as the single most effective public health measure to help prevent tooth decay.

  • MWRA adds fluoride at its Carroll Water Treatment Plant, which serves 47 communities in eastern and metro west Massachusetts, including Boston.
  • MWRA gets fluoride from Univar, Inc., which manufactures it in Spruce Pine, North Carolina or Aurora North Carolina.
  • Fluoride is not added to MWRA's three Chicopee Valley Aqueduct (CVA) communities: Chicopee, South Hadley and Wilbraham.

The US Centers for Disease Control and Prevention (the CDC), one of the world’s leading public health institutions, takes  strong position toward promoting fluoridation to reduce tooth decay and promote community public health. The CDC is highly regarded for its scientific expertise and objectivity, and it is important to MWRA that CDC’s position on fluoridation is unequivocal. The summary of CDC’s views is included in the document: Achievements in Public Health, 1900 to 1999: Fluoridation to Prevent Dental Cavities. The also CDC published a report, Ten Great Public Health Achievements — United States 1900-1999 (PDF), that listed fluoridation of public water supplies to reduce dental cavities as one of the leading public health achievements of the entire century.

Our approach is reinforced by the views of other organizations with strong public health and medical credentials that also support fluoridation including the Massachusetts Department of Public Health, the World Health Organization, the American Dental Association and American Academy of Pediatrics.

The Environmental Protection Agency (EPA) sets fluoride standards to guard drinking water safety. For fluoride, 4.0 parts per million is the Maximum Contaminant Level Goal (MCLG), the level below which there is no known or expected risk to health. MWRA’s level of 0.7 parts per million are well below the EPA MCLG.

In 2015, MWRA lowered the amount of fluoride added to the water it supplies in accordance with a new recommendation from the Centers for Disease Control (CDC). On April 27, 2015, the CDC released a recommendation that water suppliers reduce their fluoride dosage to 0.7 milligrams per liter (mg/l) from a range between 0.7 mg/l and 1.2 mg/l. According to the CDC, the dose was lowered because Americans now receive fluoride from a variety of sources other than just water, and the dental benefits can be achieved with a lower dose in water. 

“MWRA has been adding fluoride to the water since the 1970's to reduce tooth decay and promote community public health,” said Fred Laskey, MWRA’s executive director. “Like most other water suppliers, we follow the recommendations of the CDC, as well as the World Health Organization and the American Dental Association. These are the public health experts and we look to them for guidance on this important issue.”

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Updated June 12, 2023

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