Fluoride
Cornell Waterworks
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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.730 ppm | 25 | 25 | 0.0690 ppm - 0.906 ppm |
| 2015 | 0.761 ppm | 24 | 24 | 0.610 ppm - 0.910 ppm |
| 2016 | 0.799 ppm | 24 | 24 | 0.650 ppm - 1.06 ppm |
| 2017 | 0.798 ppm | 25 | 25 | 0.690 ppm - 0.990 ppm |
| 2018 | 0.767 ppm | 24 | 24 | 0.660 ppm - 0.844 ppm |
| 2019 | 0.706 ppm | 24 | 24 | 0.610 ppm - 0.790 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 |
|---|---|---|
| 2014-01-15 | 116517001 | 0.691 ppm |
| 2014-01-15 | 116517001 | 0.710 ppm |
| 2014-02-27 | 121247001 | 0.770 ppm |
| 2014-02-27 | 121247001 | 0.793 ppm |
| 2014-03-04 | 772803 | 0.0690 ppm |
| 2014-03-19 | 124421001 | 0.690 ppm |
| 2014-03-19 | 124421001 | 0.710 ppm |
| 2014-04-16 | 128242001 | 0.742 ppm |
| 2014-04-16 | 128242001 | 0.820 ppm |
| 2014-05-14 | 133084001 | 0.860 ppm |
| 2014-05-14 | 133084001 | 0.906 ppm |
| 2014-06-23 | 141051001 | 0.810 ppm |
| 2014-06-23 | 141051001 | 0.865 ppm |
| 2014-07-16 | 146037001 | 0.820 ppm |
| 2014-07-16 | 146037001 | 0.877 ppm |
| 2014-08-27 | 154176001 | 0.672 ppm |
| 2014-08-27 | 154176001 | 0.780 ppm |
| 2014-09-24 | 159919001 | 0.750 ppm |
| 2014-09-24 | 159919001 | 0.856 ppm |
| 2014-10-22 | 165299001 | 0.780 ppm |
| 2014-10-22 | 165299001 | 0.882 ppm |
| 2014-11-19 | 169563001 | 0.414 ppm |
| 2014-11-19 | 169563001 | 0.450 ppm |
| 2014-12-22 | 173804001 | 0.740 ppm |
| 2014-12-22 | 173804001 | 0.798 ppm |
| 2015-01-22 | 176921001 | 0.610 ppm |
| 2015-01-22 | 176921001 | 0.660 ppm |
| 2015-02-24 | 180985001 | 0.656 ppm |
| 2015-02-24 | 180985001 | 0.830 ppm |
| 2015-03-17 | 184423001 | 0.630 ppm |
| 2015-03-17 | 184423001 | 0.631 ppm |
| 2015-04-21 | 189579001 | 0.650 ppm |
| 2015-04-21 | 189579001 | 0.675 ppm |
| 2015-05-26 | 195791001 | 0.700 ppm |
| 2015-05-26 | 195791001 | 0.739 ppm |
| 2015-06-24 | 202071001 | 0.700 ppm |
| 2015-06-24 | 202071001 | 0.789 ppm |
| 2015-07-21 | 207572001 | 0.796 ppm |
| 2015-07-21 | 207572001 | 0.860 ppm |
| 2015-08-17 | 212500001 | 0.790 ppm |
| 2015-08-17 | 212500001 | 0.800 ppm |
| 2015-09-23 | 220166001 | 0.730 ppm |
| 2015-09-23 | 220166001 | 0.847 ppm |
| 2015-10-27 | 225918001 | 0.780 ppm |
| 2015-10-27 | 225918001 | 0.890 ppm |
| 2015-11-18 | 229575001 | 0.841 ppm |
| 2015-11-18 | 229575001 | 0.890 ppm |
| 2015-12-09 | 232400001 | 0.864 ppm |
| 2015-12-09 | 232400001 | 0.910 ppm |
| 2016-01-26 | 237287001 | 0.823 ppm |
| 2016-01-26 | 237287001 | 0.830 ppm |
| 2016-02-17 | 240408001 | 0.770 ppm |
| 2016-02-17 | 240408001 | 0.868 ppm |
| 2016-03-23 | 245593001 | 0.840 ppm |
| 2016-03-23 | 245593001 | 0.885 ppm |
| 2016-04-26 | 251119001 | 0.810 ppm |
| 2016-04-26 | 251119001 | 1.06 ppm |
| 2016-05-25 | 257005001 | 0.730 ppm |
| 2016-05-25 | 257005001 | 0.863 ppm |
| 2016-06-29 | 263456001 | 0.720 ppm |
| 2016-06-29 | 263456001 | 0.826 ppm |
| 2016-07-25 | 268713001 | 0.750 ppm |
| 2016-07-25 | 268713001 | 0.820 ppm |
| 2016-08-24 | 274383001 | 0.720 ppm |
| 2016-08-24 | 274383001 | 0.750 ppm |
| 2016-09-14 | 278139001 | 0.743 ppm |
| 2016-09-14 | 278139001 | 0.840 ppm |
| 2016-10-24 | 285862001 | 0.695 ppm |
| 2016-10-24 | 285862001 | 0.700 ppm |
| 2016-11-28 | 290603001 | 0.784 ppm |
| 2016-11-28 | 290603001 | 0.880 ppm |
| 2016-12-21 | 294105001 | 0.650 ppm |
| 2016-12-21 | 294105001 | 0.812 ppm |
| 2017-01-18 | 296842001 | 0.690 ppm |
| 2017-01-18 | 296842001 | 0.805 ppm |
| 2017-02-15 | 300484001 | 0.720 ppm |
| 2017-02-15 | 300484001 | 0.789 ppm |
| 2017-03-21 | 305623001 | 0.770 ppm |
| 2017-03-21 | 305623001 | 0.802 ppm |
| 2017-04-12 | 982822 | 0.990 ppm |
| 2017-04-19 | 311149001 | 0.700 ppm |
| 2017-04-19 | 311149001 | 0.821 ppm |
| 2017-05-17 | 316780001 | 0.810 ppm |
| 2017-05-17 | 316780001 | 0.813 ppm |
| 2017-06-27 | 325038001 | 0.830 ppm |
| 2017-06-27 | 325038001 | 0.836 ppm |
| 2017-07-24 | 330936001 | 0.800 ppm |
| 2017-07-24 | 330936001 | 0.828 ppm |
| 2017-08-16 | 336567001 | 0.710 ppm |
| 2017-08-16 | 336567001 | 0.825 ppm |
| 2017-09-18 | 343205001 | 0.760 ppm |
| 2017-09-18 | 343205001 | 0.810 ppm |
| 2017-10-24 | 350949001 | 0.810 ppm |
| 2017-10-24 | 350949001 | 0.835 ppm |
| 2017-11-28 | 356511001 | 0.799 ppm |
| 2017-11-28 | 356511001 | 0.800 ppm |
| 2017-12-13 | 359494001 | 0.760 ppm |
| 2017-12-13 | 359494001 | 0.847 ppm |
| 2018-01-16 | 363153001 | 0.730 ppm |
| 2018-01-16 | 363153001 | 0.815 ppm |
| 2018-02-21 | 368206001 | 0.720 ppm |
| 2018-02-21 | 368206001 | 0.796 ppm |
| 2018-03-14 | 371422001 | 0.660 ppm |
| 2018-03-14 | 371422001 | 0.781 ppm |
| 2018-04-18 | 377266001 | 0.780 ppm |
| 2018-04-18 | 377266001 | 0.834 ppm |
| 2018-05-16 | 383025001 | 0.720 ppm |
| 2018-05-16 | 383025001 | 0.775 ppm |
| 2018-06-27 | 391525001 | 0.680 ppm |
| 2018-06-27 | 391525001 | 0.809 ppm |
| 2018-07-18 | 395652001 | 0.690 ppm |
| 2018-07-18 | 395652001 | 0.806 ppm |
| 2018-08-29 | 404317001 | 0.758 ppm |
| 2018-08-29 | 404317001 | 0.760 ppm |
| 2018-09-19 | 409399001 | 0.780 ppm |
| 2018-09-19 | 409399001 | 0.818 ppm |
| 2018-10-24 | 416448001 | 0.710 ppm |
| 2018-10-24 | 416448001 | 0.794 ppm |
| 2018-11-21 | 420921001 | 0.780 ppm |
| 2018-11-21 | 420921001 | 0.844 ppm |
| 2018-12-12 | 424301001 | 0.750 ppm |
| 2018-12-12 | 424301001 | 0.819 ppm |
| 2019-01-23 | 429001001 | 0.776 ppm |
| 2019-01-23 | 429001001 | 0.790 ppm |
| 2019-02-20 | 432573001 | 0.721 ppm |
| 2019-02-20 | 432573001 | 0.740 ppm |
| 2019-03-27 | 437562001 | 0.704 ppm |
| 2019-03-27 | 437562001 | 0.750 ppm |
| 2019-04-17 | 441278001 | 0.710 ppm |
| 2019-04-17 | 441278001 | 0.730 ppm |
| 2019-05-22 | 447837001 | 0.674 ppm |
| 2019-05-22 | 447837001 | 0.740 ppm |
| 2019-06-19 | 453106001 | 0.675 ppm |
| 2019-06-19 | 453106001 | 0.770 ppm |
| 2019-07-24 | 459915001 | 0.640 ppm |
| 2019-07-24 | 459915001 | 0.670 ppm |
| 2019-08-21 | 465499001 | 0.667 ppm |
| 2019-08-21 | 465499001 | 0.700 ppm |
| 2019-09-18 | 471362001 | 0.692 ppm |
| 2019-09-18 | 471362001 | 0.760 ppm |
| 2019-10-09 | 475731001 | 0.686 ppm |
| 2019-10-09 | 475731001 | 0.730 ppm |
| 2019-11-06 | 480482001 | 0.670 ppm |
| 2019-11-06 | 480482001 | 0.720 ppm |
| 2019-12-11 | 485855001 | 0.610 ppm |
| 2019-12-11 | 485855001 | 0.630 ppm |