Fluoride
Wisconsin Dells 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 | 0.645 ppm | 24 | 24 | 0.475 ppm - 0.756 ppm |
| 2019 | 0.672 ppm | 24 | 24 | 0.543 ppm - 0.826 ppm |
| 2020 | 0.587 ppm | 26 | 25 | ND - 0.768 ppm |
| 2021 | 0.582 ppm | 28 | 28 | 0.466 ppm - 0.706 ppm |
| 2022 | 0.607 ppm | 24 | 24 | 0.454 ppm - 0.671 ppm |
| 2023 | 0.551 ppm | 30 | 28 | ND - 0.670 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 |
|---|---|---|
| 2018-01-29 | 364669001 | 0.621 ppm |
| 2018-01-29 | 364669001 | 0.650 ppm |
| 2018-02-07 | 366079001 | 0.680 ppm |
| 2018-02-07 | 366079001 | 0.756 ppm |
| 2018-03-19 | 371916001 | 0.658 ppm |
| 2018-03-19 | 371916001 | 0.700 ppm |
| 2018-04-24 | 378155001 | 0.475 ppm |
| 2018-04-24 | 378155001 | 0.680 ppm |
| 2018-05-17 | 383167001 | 0.589 ppm |
| 2018-05-17 | 383167001 | 0.740 ppm |
| 2018-06-04 | 386164001 | 0.641 ppm |
| 2018-06-04 | 386164001 | 0.690 ppm |
| 2018-07-20 | 395863001 | 0.615 ppm |
| 2018-07-20 | 395863001 | 0.670 ppm |
| 2018-08-14 | 401235001 | 0.538 ppm |
| 2018-08-14 | 401235001 | 0.630 ppm |
| 2018-09-21 | 409596001 | 0.491 ppm |
| 2018-09-21 | 409596001 | 0.690 ppm |
| 2018-10-03 | 412503001 | 0.613 ppm |
| 2018-10-03 | 412503001 | 0.670 ppm |
| 2018-11-02 | 417508001 | 0.680 ppm |
| 2018-11-02 | 417508001 | 0.748 ppm |
| 2018-12-18 | 425159001 | 0.569 ppm |
| 2018-12-18 | 425159001 | 0.690 ppm |
| 2019-01-16 | 428250001 | 0.543 ppm |
| 2019-01-16 | 428250001 | 0.670 ppm |
| 2019-02-22 | 432672001 | 0.556 ppm |
| 2019-02-22 | 432672001 | 0.710 ppm |
| 2019-03-15 | 435568001 | 0.555 ppm |
| 2019-03-15 | 435568001 | 0.690 ppm |
| 2019-04-23 | 442123001 | 0.658 ppm |
| 2019-04-23 | 442123001 | 0.720 ppm |
| 2019-05-22 | 447840001 | 0.642 ppm |
| 2019-05-22 | 447840001 | 0.690 ppm |
| 2019-06-13 | 451778001 | 0.640 ppm |
| 2019-06-13 | 451778001 | 0.826 ppm |
| 2019-07-12 | 457238001 | 0.690 ppm |
| 2019-07-12 | 457238001 | 0.691 ppm |
| 2019-08-19 | 464776001 | 0.690 ppm |
| 2019-08-19 | 464776001 | 0.699 ppm |
| 2019-09-05 | 467919001 | 0.657 ppm |
| 2019-09-05 | 467919001 | 0.680 ppm |
| 2019-10-25 | 478247001 | 0.680 ppm |
| 2019-10-25 | 478247001 | 0.690 ppm |
| 2019-11-26 | 483473001 | 0.660 ppm |
| 2019-11-26 | 483473001 | 0.677 ppm |
| 2019-12-13 | 486017001 | 0.691 ppm |
| 2019-12-13 | 486017001 | 0.730 ppm |
| 2020-01-20 | 490320001 | 0.454 ppm |
| 2020-01-20 | 490320001 | 0.650 ppm |
| 2020-04-23 | 501973001 | 0.640 ppm |
| 2020-04-23 | 501973001 | 0.659 ppm |
| 2020-05-08 | 503844001 | 0.660 ppm |
| 2020-05-08 | 503844001 | 0.695 ppm |
| 2020-06-10 | 509285001 | 0.620 ppm |
| 2020-06-10 | 509285001 | 0.686 ppm |
| 2020-07-23 | 516452001 | 0.639 ppm |
| 2020-07-23 | 516452001 | 0.640 ppm |
| 2020-08-18 | 520889001 | 0.597 ppm |
| 2020-08-18 | 520889001 | 0.660 ppm |
| 2020-09-10 | 471857 | 0.560 ppm |
| 2020-09-11 | 472173 | ND |
| 2020-09-11 | 472181 | 0.300 ppm |
| 2020-09-11 | 472165 | 0.590 ppm |
| 2020-09-11 | 472170 | 0.610 ppm |
| 2020-09-11 | 472185 | 0.650 ppm |
| 2020-09-24 | 527758001 | 0.620 ppm |
| 2020-09-24 | 527758001 | 0.768 ppm |
| 2020-10-27 | 533471001 | 0.598 ppm |
| 2020-10-27 | 533471001 | 0.640 ppm |
| 2020-11-23 | 537370001 | 0.544 ppm |
| 2020-11-23 | 537370001 | 0.640 ppm |
| 2020-12-17 | 540988001 | 0.519 ppm |
| 2020-12-17 | 540988001 | 0.620 ppm |
| 2021-01-28 | 545428001 | 0.489 ppm |
| 2021-01-28 | 545428001 | 0.570 ppm |
| 2021-02-23 | 548872001 | 0.466 ppm |
| 2021-02-23 | 548872001 | 0.560 ppm |
| 2021-02-23 | 548872001 | 0.466 ppm |
| 2021-02-23 | 548872001 | 0.560 ppm |
| 2021-03-17 | 552387001 | 0.500 ppm |
| 2021-03-17 | 552387001 | 0.570 ppm |
| 2021-03-17 | 552387001 | 0.500 ppm |
| 2021-03-17 | 552387001 | 0.570 ppm |
| 2021-04-06 | 555226001 | 0.582 ppm |
| 2021-04-06 | 555226001 | 0.650 ppm |
| 2021-05-11 | 561416001 | 0.582 ppm |
| 2021-05-11 | 561416001 | 0.620 ppm |
| 2021-06-21 | 568278001 | 0.528 ppm |
| 2021-06-21 | 568278001 | 0.600 ppm |
| 2021-07-08 | 571183001 | 0.610 ppm |
| 2021-07-08 | 571183001 | 0.612 ppm |
| 2021-08-19 | 579484001 | 0.610 ppm |
| 2021-08-19 | 579484001 | 0.652 ppm |
| 2021-09-17 | 584351001 | 0.623 ppm |
| 2021-09-17 | 584351001 | 0.630 ppm |
| 2021-10-19 | 590649001 | 0.640 ppm |
| 2021-10-19 | 590649001 | 0.706 ppm |
| 2021-11-29 | 596132001 | 0.573 ppm |
| 2021-11-29 | 596132001 | 0.680 ppm |
| 2021-12-07 | 597777001 | 0.538 ppm |
| 2021-12-07 | 597777001 | 0.620 ppm |
| 2022-01-06 | 601053001 | 0.508 ppm |
| 2022-01-06 | 601053001 | 0.660 ppm |
| 2022-02-25 | 607181001 | 0.623 ppm |
| 2022-02-25 | 607181001 | 0.660 ppm |
| 2022-03-08 | 608766001 | 0.487 ppm |
| 2022-03-08 | 608766001 | 0.630 ppm |
| 2022-04-12 | 613918001 | 0.567 ppm |
| 2022-04-12 | 613918001 | 0.660 ppm |
| 2022-05-16 | 620701001 | 0.581 ppm |
| 2022-05-16 | 620701001 | 0.630 ppm |
| 2022-06-16 | 625852001 | 0.454 ppm |
| 2022-06-16 | 625852001 | 0.620 ppm |
| 2022-07-16 | 632315001 | 0.490 ppm |
| 2022-07-16 | 632315001 | 0.620 ppm |
| 2022-08-17 | 637789001 | 0.630 ppm |
| 2022-08-17 | 637789001 | 0.671 ppm |
| 2022-09-08 | 641478001 | 0.640 ppm |
| 2022-09-08 | 641478001 | 0.649 ppm |
| 2022-10-12 | 648585001 | 0.545 ppm |
| 2022-10-12 | 648585001 | 0.640 ppm |
| 2022-11-02 | 651641001 | 0.660 ppm |
| 2022-11-02 | 651641001 | 0.664 ppm |
| 2022-12-06 | 656985001 | 0.619 ppm |
| 2022-12-06 | 656985001 | 0.660 ppm |
| 2023-01-24 | 662282001 | 0.579 ppm |
| 2023-01-24 | 662282001 | 0.630 ppm |
| 2023-02-16 | 665119001 | 0.575 ppm |
| 2023-02-16 | 665119001 | 0.650 ppm |
| 2023-03-28 | 670319001 | 0.483 ppm |
| 2023-03-28 | 670319001 | 0.660 ppm |
| 2023-04-20 | 674631001 | 0.453 ppm |
| 2023-04-20 | 674631001 | 0.630 ppm |
| 2023-04-26 | 1317740 | ND |
| 2023-04-26 | 1317742 | ND |
| 2023-05-23 | 1327862 | 0.390 ppm |
| 2023-05-23 | 680576001 | 0.493 ppm |
| 2023-05-23 | 680576001 | 0.660 ppm |
| 2023-06-15 | 684153001 | 0.539 ppm |
| 2023-06-15 | 684153001 | 0.660 ppm |
| 2023-06-20 | 1337391 | 0.610 ppm |
| 2023-07-18 | 1349249 | 0.430 ppm |
| 2023-07-18 | 1349253 | 0.570 ppm |
| 2023-07-24 | 690824001 | 0.594 ppm |
| 2023-07-24 | 690824001 | 0.650 ppm |
| 2023-08-28 | 697363001 | 0.523 ppm |
| 2023-08-28 | 697363001 | 0.620 ppm |
| 2023-09-26 | 703210001 | 0.645 ppm |
| 2023-09-26 | 703210001 | 0.650 ppm |
| 2023-10-18 | 707325001 | 0.629 ppm |
| 2023-10-18 | 707325001 | 0.650 ppm |
| 2023-11-14 | 711498001 | 0.631 ppm |
| 2023-11-14 | 711498001 | 0.670 ppm |
| 2023-12-07 | 713889001 | 0.616 ppm |
| 2023-12-07 | 713889001 | 0.640 ppm |