Fluoride
Loyal Waterworks
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems to prevent cavities and support oral health in people.
In 2015, the Department of Health and Human Services updated its recommendation of an optimal level of 0.7 parts per million, or ppm, added to drinking water based on the health benefits of tooth decay prevention. Studies have shown that fluoride added to community water systems at this level reduces dental cavities, especially in children.
And studies have conclusively shown that fluoride in toothpaste and mouthwash can also provide these benefits.
Read More.
Health Concerns
Although the HHS-recommended level of 0.7 ppm can help promote oral health in children and adults, this level is likely too high for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water.
And fluoride in water at higher levels can be detrimental for everyone, especially children.
Long-term ingestion of higher levels of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth in children.
A 2024 authoritative assessment by the National Toxicology Program found that higher levels of fluoride exposure, such as drinking water containing more than 1.5 ppm of fluoride, are associated with lower IQ in children. The conclusion was based on studies in human populations outside of the U.S.
Affecting systems with naturally occurring fluoride, 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 fracture. But these effects may occur at lower levels of exposure, raising concerns that the current limit may not adequately protect public health.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2018 | 0.634 ppm | 24 | 24 | 0.479 ppm - 0.800 ppm |
| 2019 | 0.705 ppm | 24 | 24 | 0.551 ppm - 0.800 ppm |
| 2020 | 0.562 ppm | 24 | 24 | 0.200 ppm - 0.720 ppm |
| 2021 | 0.630 ppm | 28 | 28 | 0.560 ppm - 0.740 ppm |
| 2022 | 0.647 ppm | 24 | 24 | 0.440 ppm - 0.795 ppm |
| 2023 | 0.681 ppm | 28 | 28 | 0.120 ppm - 0.790 ppm |
ppm = parts per million
State, National, and Health Guidelines for Drinking Water
EPA Maximum Contaminant
Level (MCL): 4 ppm
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-09 | 362363001 | 0.610 ppm |
| 2018-01-09 | 362363001 | 0.635 ppm |
| 2018-02-14 | 367173001 | 0.577 ppm |
| 2018-02-14 | 367173001 | 0.700 ppm |
| 2018-03-19 | 371911001 | 0.479 ppm |
| 2018-03-19 | 371911001 | 0.560 ppm |
| 2018-04-11 | 376104001 | 0.564 ppm |
| 2018-04-11 | 376104001 | 0.570 ppm |
| 2018-05-02 | 379776001 | 0.480 ppm |
| 2018-05-02 | 379776001 | 0.560 ppm |
| 2018-06-19 | 389888001 | 0.558 ppm |
| 2018-06-19 | 389888001 | 0.580 ppm |
| 2018-07-09 | 393025001 | 0.672 ppm |
| 2018-07-09 | 393025001 | 0.680 ppm |
| 2018-08-06 | 399157001 | 0.627 ppm |
| 2018-08-06 | 399157001 | 0.730 ppm |
| 2018-09-25 | 410569001 | 0.739 ppm |
| 2018-09-25 | 410569001 | 0.800 ppm |
| 2018-10-02 | 412245001 | 0.738 ppm |
| 2018-10-02 | 412245001 | 0.800 ppm |
| 2018-11-05 | 418084001 | 0.661 ppm |
| 2018-11-05 | 418084001 | 0.700 ppm |
| 2018-12-12 | 424240001 | 0.580 ppm |
| 2018-12-12 | 424240001 | 0.604 ppm |
| 2019-01-14 | 427842001 | 0.737 ppm |
| 2019-01-14 | 427842001 | 0.800 ppm |
| 2019-02-20 | 432532001 | 0.740 ppm |
| 2019-02-20 | 432532001 | 0.750 ppm |
| 2019-03-18 | 435963001 | 0.730 ppm |
| 2019-03-18 | 435963001 | 0.734 ppm |
| 2019-04-08 | 439435001 | 0.690 ppm |
| 2019-04-08 | 439435001 | 0.704 ppm |
| 2019-05-08 | 445111001 | 0.693 ppm |
| 2019-05-08 | 445111001 | 0.790 ppm |
| 2019-06-05 | 450218001 | 0.683 ppm |
| 2019-06-05 | 450218001 | 0.760 ppm |
| 2019-07-08 | 456245001 | 0.551 ppm |
| 2019-07-08 | 456245001 | 0.670 ppm |
| 2019-08-05 | 461705001 | 0.690 ppm |
| 2019-08-05 | 461705001 | 0.750 ppm |
| 2019-09-03 | 467509001 | 0.765 ppm |
| 2019-09-03 | 467509001 | 0.800 ppm |
| 2019-10-01 | 473960001 | 0.660 ppm |
| 2019-10-01 | 473960001 | 0.670 ppm |
| 2019-11-05 | 480025001 | 0.597 ppm |
| 2019-11-05 | 480025001 | 0.630 ppm |
| 2019-12-09 | 485204001 | 0.658 ppm |
| 2019-12-09 | 485204001 | 0.660 ppm |
| 2020-01-08 | 488585001 | 0.593 ppm |
| 2020-01-08 | 488585001 | 0.680 ppm |
| 2020-04-07 | 500152001 | 0.589 ppm |
| 2020-04-07 | 500152001 | 0.630 ppm |
| 2020-04-23 | 20D0780-02 | 0.200 ppm |
| 2020-04-23 | 20D0780-03 | 0.220 ppm |
| 2020-04-23 | 20D0780-01 | 0.500 ppm |
| 2020-04-23 | 20D0780-04 | 0.650 ppm |
| 2020-05-04 | 503064001 | 0.534 ppm |
| 2020-05-04 | 503064001 | 0.610 ppm |
| 2020-06-01 | 507411001 | 0.499 ppm |
| 2020-06-01 | 507411001 | 0.540 ppm |
| 2020-07-14 | 514854001 | 0.482 ppm |
| 2020-07-14 | 514854001 | 0.600 ppm |
| 2020-08-03 | 517984001 | 0.549 ppm |
| 2020-08-03 | 517984001 | 0.560 ppm |
| 2020-09-01 | 523111001 | 0.553 ppm |
| 2020-09-01 | 523111001 | 0.580 ppm |
| 2020-10-05 | 529528001 | 0.633 ppm |
| 2020-10-05 | 529528001 | 0.720 ppm |
| 2020-11-02 | 534283001 | 0.610 ppm |
| 2020-11-02 | 534283001 | 0.680 ppm |
| 2020-12-01 | 538342001 | 0.630 ppm |
| 2020-12-01 | 538342001 | 0.641 ppm |
| 2021-01-04 | 542004001 | 0.632 ppm |
| 2021-01-04 | 542004001 | 0.680 ppm |
| 2021-02-02 | 546253001 | 0.570 ppm |
| 2021-02-02 | 546253001 | 0.581 ppm |
| 2021-02-02 | 546253001 | 0.570 ppm |
| 2021-02-02 | 546253001 | 0.581 ppm |
| 2021-03-02 | 549885001 | 0.620 ppm |
| 2021-03-02 | 549885001 | 0.634 ppm |
| 2021-03-02 | 549885001 | 0.620 ppm |
| 2021-03-02 | 549885001 | 0.634 ppm |
| 2021-04-06 | 555010001 | 0.630 ppm |
| 2021-04-06 | 555010001 | 0.639 ppm |
| 2021-05-03 | 559748001 | 0.640 ppm |
| 2021-05-03 | 559748001 | 0.653 ppm |
| 2021-06-07 | 565566001 | 0.625 ppm |
| 2021-06-07 | 565566001 | 0.680 ppm |
| 2021-07-26 | 574570001 | 0.600 ppm |
| 2021-07-26 | 574570001 | 0.610 ppm |
| 2021-08-09 | 577081001 | 0.590 ppm |
| 2021-08-09 | 577081001 | 0.630 ppm |
| 2021-09-07 | 582209001 | 0.560 ppm |
| 2021-09-07 | 582209001 | 0.610 ppm |
| 2021-10-04 | 587732001 | 0.580 ppm |
| 2021-10-04 | 587732001 | 0.638 ppm |
| 2021-11-08 | 593672001 | 0.670 ppm |
| 2021-11-08 | 593672001 | 0.716 ppm |
| 2021-12-13 | 598372001 | 0.716 ppm |
| 2021-12-13 | 598372001 | 0.740 ppm |
| 2022-01-03 | 600389001 | 0.720 ppm |
| 2022-01-03 | 600389001 | 0.728 ppm |
| 2022-02-08 | 605125001 | 0.650 ppm |
| 2022-02-08 | 605125001 | 0.693 ppm |
| 2022-03-01 | 607621001 | 0.657 ppm |
| 2022-03-01 | 607621001 | 0.670 ppm |
| 2022-04-04 | 612153001 | 0.668 ppm |
| 2022-04-04 | 612153001 | 0.710 ppm |
| 2022-05-02 | 616903001 | 0.590 ppm |
| 2022-05-02 | 616903001 | 0.634 ppm |
| 2022-06-06 | 623496001 | 0.480 ppm |
| 2022-06-06 | 623496001 | 0.524 ppm |
| 2022-07-05 | 628676001 | 0.620 ppm |
| 2022-07-05 | 628676001 | 0.762 ppm |
| 2022-08-01 | 634319001 | 0.610 ppm |
| 2022-08-01 | 634319001 | 0.632 ppm |
| 2022-09-12 | 642067001 | 0.440 ppm |
| 2022-09-12 | 642067001 | 0.535 ppm |
| 2022-10-03 | 646425001 | 0.690 ppm |
| 2022-10-03 | 646425001 | 0.795 ppm |
| 2022-11-07 | 652096001 | 0.600 ppm |
| 2022-11-07 | 652096001 | 0.743 ppm |
| 2022-12-05 | 655678001 | 0.610 ppm |
| 2022-12-05 | 655678001 | 0.758 ppm |
| 2023-01-09 | 659818001 | 0.720 ppm |
| 2023-01-09 | 659818001 | 0.750 ppm |
| 2023-02-06 | 663444001 | 0.740 ppm |
| 2023-02-06 | 663444001 | 0.781 ppm |
| 2023-03-07 | 667520001 | 0.750 ppm |
| 2023-03-07 | 667520001 | 0.753 ppm |
| 2023-04-03 | 671606001 | 0.663 ppm |
| 2023-04-03 | 671606001 | 0.720 ppm |
| 2023-05-01 | 676044001 | 0.710 ppm |
| 2023-05-01 | 676044001 | 0.730 ppm |
| 2023-05-08 | 23E0244-05 | 0.120 ppm |
| 2023-05-08 | 23E0244-04 | 0.440 ppm |
| 2023-05-08 | 23E0244-01 | 0.620 ppm |
| 2023-05-08 | 23E0244-02 | 0.720 ppm |
| 2023-06-05 | 682081001 | 0.710 ppm |
| 2023-06-05 | 682081001 | 0.733 ppm |
| 2023-07-10 | 687920001 | 0.710 ppm |
| 2023-07-10 | 687920001 | 0.746 ppm |
| 2023-08-08 | 693840001 | 0.763 ppm |
| 2023-08-08 | 693840001 | 0.790 ppm |
| 2023-09-11 | 699642001 | 0.720 ppm |
| 2023-09-11 | 699642001 | 0.740 ppm |
| 2023-10-09 | 705171001 | 0.585 ppm |
| 2023-10-09 | 705171001 | 0.650 ppm |
| 2023-11-07 | 709905001 | 0.645 ppm |
| 2023-11-07 | 709905001 | 0.720 ppm |
| 2023-12-04 | 713101001 | 0.646 ppm |
| 2023-12-04 | 713101001 | 0.700 ppm |