Fluoride
Danbury Water Department
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems. Read More.
Fluoride has been promoted as a chemical that reduces dental cavities. Yet it is now well-established that fluoride primarily exerts its protective effects through topical mechanisms, such as sodium fluoride in toothpaste and mouthwash. In contrast, long-term ingestion of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth. EPA's maximum legal limit is set at 4 parts per million (ppm) to prevent skeletal fluorosis, a condition where bones become brittle and more susceptible to fractures, although these effects may occur at lower doses.
Even fluoride levels of 0.7 ppm, the amount of fluoride in drinking water recommended by the U.S. Public Health Service, can result in too much fluoride for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water. The National Toxicology Program is investigating the potential for low doses of fluoride to alter thyroid function and childhood brain development.
Testing results - average by year
Year | Average result | Samples taken | Detections | Range of results |
---|---|---|---|---|
2014 | 0.305 ppm | 6 | 3 | ND - 0.950 ppm |
2015 | 0.438 ppm | 4 | 2 | ND - 0.890 ppm |
2016 | 0.230 ppm | 6 | 3 | ND - 0.650 ppm |
2017 | 0.333 ppm | 4 | 2 | ND - 0.740 ppm |
2018 | 0.358 ppm | 4 | 4 | 0.0300 ppm - 0.650 ppm |
2019 | 0.302 ppm | 5 | 5 | 0.0400 ppm - 0.730 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EPA Maximum Contaminant
Level (MCL) 4 ppm
ppm = parts per million
All test results
Date | Lab ID | Result |
---|---|---|
2014-06-24 | E406M77-2IOC1 | 0.680 ppm |
2014-06-24 | E406M77-3IOC1 | ND |
2014-06-24 | E406M77-4IOC1 | 0.950 ppm |
2014-06-24 | E406M77-1IOC1 | 0.200 ppm |
2014-10-21 | E410J14-1IOC1 | ND |
2014-10-21 | E410J14-3IOC1 | ND |
2015-05-05 | E505239-3IOC1 | 0.890 ppm |
2015-05-05 | E505239-4IOC1 | 0.860 ppm |
2015-05-05 | E505239-2IOC1 | ND |
2015-05-05 | E505239-1IOC1 | ND |
2016-08-09 | 187079CH | 0.650 ppm |
2016-08-09 | 187077CH | 0.650 ppm |
2016-08-09 | 187076GE | ND |
2016-08-09 | 187078GE | ND |
2016-12-14 | 192746GE | 0.0800 ppm |
2016-12-14 | 192751GE | ND |
2017-05-18 | 198891GE | 0.740 ppm |
2017-05-18 | 198890GE | 0.590 ppm |
2017-06-15 | 200358GE | ND |
2017-06-15 | 200361GE | ND |
2018-04-12 | 212687GE | 0.0300 ppm |
2018-04-12 | 212690GE | 0.110 ppm |
2018-10-12 | IOC1 200508940 | 0.640 ppm |
2018-10-12 | IOC1 200508939 | 0.650 ppm |
2019-04-11 | IOC1 200528182 | 0.730 ppm |
2019-04-11 | IOC1 200528181 | 0.620 ppm |
2019-04-11 | IOCR 200528185 | 0.0500 ppm |
2019-04-11 | IOCR 200528187 | 0.0400 ppm |
2019-05-16 | IOCR 200532591A | 0.0700 ppm |