Fluoride
Hartington, City of
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 | 1.05 ppm | 13 | 13 | 0.920 ppm - 1.46 ppm |
2015 | 0.860 ppm | 14 | 13 | ND - 1.22 ppm |
2016 | 0.989 ppm | 13 | 13 | 0.329 ppm - 1.78 ppm |
2017 | 1.04 ppm | 13 | 13 | 0.261 ppm - 1.52 ppm |
2018 | 1.14 ppm | 12 | 12 | 0.951 ppm - 1.83 ppm |
2019 | 1.17 ppm | 12 | 12 | 0.918 ppm - 1.84 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 |
---|---|---|
2014-01-13 | 279226 | 1.07 ppm |
2014-02-11 | 284634 | 0.965 ppm |
2014-03-11 | 288666 | 1.000 ppm |
2014-04-15 | 291892 | 0.973 ppm |
2014-05-12 | 297681 | 0.959 ppm |
2014-06-10 | 304012 | 0.950 ppm |
2014-07-07 | 310075 | 1.46 ppm |
2014-07-14 | 308940 | 0.920 ppm |
2014-08-11 | 315476 | 0.987 ppm |
2014-09-09 | 321380 | 1.18 ppm |
2014-10-07 | 326148 | 1.15 ppm |
2014-11-04 | 333547 | 0.983 ppm |
2014-12-03 | 337228 | 1.01 ppm |
2015-01-13 | 341107 | 1.04 ppm |
2015-01-26 | 342769 | ND |
2015-01-26 | 342770 | 0.670 ppm |
2015-02-09 | 346700 | 1.08 ppm |
2015-03-09 | 349655 | 1.18 ppm |
2015-04-07 | 354620 | 1.01 ppm |
2015-05-13 | 362141 | 1.04 ppm |
2015-06-15 | 366665 | 0.928 ppm |
2015-07-13 | 370666 | 1.22 ppm |
2015-08-11 | 378932 | 0.982 ppm |
2015-09-08 | 384453 | 1.03 ppm |
2015-10-26 | 389312 | 0.942 ppm |
2015-11-23 | 396264 | 0.466 ppm |
2015-12-21 | 400363 | 0.447 ppm |
2016-01-26 | 0.864 ppm | |
2016-02-09 | 0.925 ppm | |
2016-03-08 | 0.965 ppm | |
2016-04-05 | 1.03 ppm | |
2016-05-10 | 1.05 ppm | |
2016-06-07 | 0.976 ppm | |
2016-07-25 | 0.384 ppm | |
2016-07-26 | 0.329 ppm | |
2016-08-22 | 0.984 ppm | |
2016-09-13 | 1.78 ppm | |
2016-10-10 | 1.18 ppm | |
2016-11-07 | 1.28 ppm | |
2016-12-19 | 1.11 ppm | |
2017-01-09 | 1.28 ppm | |
2017-02-06 | 1.04 ppm | |
2017-03-06 | 1.02 ppm | |
2017-04-10 | 1.19 ppm | |
2017-05-09 | 0.900 ppm | |
2017-06-26 | 1.15 ppm | |
2017-07-11 | 1.01 ppm | |
2017-07-31 | 0.261 ppm | |
2017-08-15 | 1.52 ppm | |
2017-09-11 | 1.09 ppm | |
2017-10-11 | 0.997 ppm | |
2017-11-14 | 0.987 ppm | |
2017-12-11 | 1.07 ppm | |
2018-01-08 | 529211 | 1.04 ppm |
2018-02-12 | 534779 | 0.951 ppm |
2018-03-12 | 538411 | 1.09 ppm |
2018-04-10 | 541396 | 1.21 ppm |
2018-05-09 | 547661 | 1.15 ppm |
2018-06-11 | 553109 | 1.08 ppm |
2018-07-09 | 557598 | 1.05 ppm |
2018-08-27 | 565348 | 1.10 ppm |
2018-09-12 | 569723 | 1.83 ppm |
2018-10-09 | 575535 | 1.01 ppm |
2018-11-19 | 581080 | 1.01 ppm |
2018-12-10 | 585071 | 1.21 ppm |
2019-01-14 | 588340 | 1.84 ppm |
2019-02-11 | 593756 | 1.12 ppm |
2019-03-13 | 597301 | 1.07 ppm |
2019-04-09 | 600949 | 1.12 ppm |
2019-05-08 | 608549 | 1.31 ppm |
2019-06-11 | 612624 | 0.960 ppm |
2019-07-08 | 617768 | 1.10 ppm |
2019-08-06 | 626228 | 1.15 ppm |
2019-09-10 | 630614 | 0.918 ppm |
2019-10-15 | 635783 | 1.35 ppm |
2019-11-13 | 642571 | 0.958 ppm |
2019-12-09 | 648207 | 1.15 ppm |