Fluoride
Shullsburg 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 | 0.719 ppm | 24 | 24 | 0.566 ppm - 0.840 ppm |
| 2019 | 0.747 ppm | 24 | 24 | 0.618 ppm - 0.911 ppm |
| 2020 | 0.709 ppm | 20 | 20 | 0.580 ppm - 0.803 ppm |
| 2021 | 0.731 ppm | 28 | 28 | 0.635 ppm - 0.884 ppm |
| 2022 | 0.732 ppm | 24 | 24 | 0.647 ppm - 0.833 ppm |
| 2023 | 0.762 ppm | 26 | 26 | 0.592 ppm - 1.37 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 |
|---|---|---|
| 2018-01-08 | 361970001 | 0.710 ppm |
| 2018-01-08 | 361970001 | 0.717 ppm |
| 2018-02-06 | 365894001 | 0.566 ppm |
| 2018-02-06 | 365894001 | 0.690 ppm |
| 2018-03-05 | 369645001 | 0.570 ppm |
| 2018-03-05 | 369645001 | 0.620 ppm |
| 2018-04-02 | 374136001 | 0.696 ppm |
| 2018-04-02 | 374136001 | 0.737 ppm |
| 2018-05-01 | 379425001 | 0.666 ppm |
| 2018-05-01 | 379425001 | 0.680 ppm |
| 2018-06-12 | 388387001 | 0.742 ppm |
| 2018-06-12 | 388387001 | 0.759 ppm |
| 2018-07-10 | 393608001 | 0.740 ppm |
| 2018-07-10 | 393608001 | 0.793 ppm |
| 2018-08-06 | 399174001 | 0.738 ppm |
| 2018-08-06 | 399174001 | 0.760 ppm |
| 2018-09-04 | 405123001 | 0.710 ppm |
| 2018-09-04 | 405123001 | 0.747 ppm |
| 2018-10-03 | 412505001 | 0.713 ppm |
| 2018-10-03 | 412505001 | 0.736 ppm |
| 2018-11-21 | 420923001 | 0.785 ppm |
| 2018-11-21 | 420923001 | 0.840 ppm |
| 2018-12-03 | 422377001 | 0.767 ppm |
| 2018-12-03 | 422377001 | 0.772 ppm |
| 2019-01-08 | 427068001 | 0.780 ppm |
| 2019-01-08 | 427068001 | 0.842 ppm |
| 2019-02-07 | 430614001 | 0.737 ppm |
| 2019-02-07 | 430614001 | 0.772 ppm |
| 2019-03-13 | 435411001 | 0.716 ppm |
| 2019-03-13 | 435411001 | 0.722 ppm |
| 2019-04-08 | 439442001 | 0.713 ppm |
| 2019-04-08 | 439442001 | 0.714 ppm |
| 2019-05-14 | 446259001 | 0.722 ppm |
| 2019-05-14 | 446259001 | 0.826 ppm |
| 2019-06-04 | 450006001 | 0.735 ppm |
| 2019-06-04 | 450006001 | 0.792 ppm |
| 2019-07-18 | 458529001 | 0.632 ppm |
| 2019-07-18 | 458529001 | 0.770 ppm |
| 2019-08-05 | 461733001 | 0.618 ppm |
| 2019-08-05 | 461733001 | 0.766 ppm |
| 2019-09-24 | 472535001 | 0.622 ppm |
| 2019-09-24 | 472535001 | 0.700 ppm |
| 2019-10-21 | 477495001 | 0.780 ppm |
| 2019-10-21 | 477495001 | 0.911 ppm |
| 2019-11-06 | 480316001 | 0.725 ppm |
| 2019-11-06 | 480316001 | 0.864 ppm |
| 2019-12-10 | 485610001 | 0.715 ppm |
| 2019-12-10 | 485610001 | 0.745 ppm |
| 2020-01-06 | 488089001 | 0.717 ppm |
| 2020-01-06 | 488089001 | 0.717 ppm |
| 2020-04-06 | 499732001 | 0.679 ppm |
| 2020-04-06 | 499732001 | 0.743 ppm |
| 2020-05-12 | 504565001 | 0.708 ppm |
| 2020-05-12 | 504565001 | 0.726 ppm |
| 2020-06-16 | 510243001 | 0.605 ppm |
| 2020-06-16 | 510243001 | 0.789 ppm |
| 2020-07-13 | 514485001 | 0.628 ppm |
| 2020-07-13 | 514485001 | 0.759 ppm |
| 2020-08-03 | 517997001 | 0.776 ppm |
| 2020-08-03 | 517997001 | 0.803 ppm |
| 2020-09-08 | 524005001 | 0.610 ppm |
| 2020-09-08 | 524005001 | 0.793 ppm |
| 2020-10-26 | 533168001 | 0.580 ppm |
| 2020-10-26 | 533168001 | 0.650 ppm |
| 2020-11-19 | 537152001 | 0.690 ppm |
| 2020-11-19 | 537152001 | 0.718 ppm |
| 2020-12-07 | 539178001 | 0.718 ppm |
| 2020-12-07 | 539178001 | 0.768 ppm |
| 2021-01-05 | 542608001 | 0.785 ppm |
| 2021-01-05 | 542608001 | 0.884 ppm |
| 2021-02-01 | 545885001 | 0.743 ppm |
| 2021-02-01 | 545885001 | 0.804 ppm |
| 2021-02-01 | 545885001 | 0.743 ppm |
| 2021-02-01 | 545885001 | 0.804 ppm |
| 2021-03-29 | 553686001 | 0.659 ppm |
| 2021-03-29 | 553686001 | 0.723 ppm |
| 2021-03-29 | 553686001 | 0.659 ppm |
| 2021-03-29 | 553686001 | 0.723 ppm |
| 2021-04-19 | 557273001 | 0.765 ppm |
| 2021-04-19 | 557273001 | 0.813 ppm |
| 2021-05-18 | 562648001 | 0.679 ppm |
| 2021-05-18 | 562648001 | 0.727 ppm |
| 2021-06-21 | 568277001 | 0.635 ppm |
| 2021-06-21 | 568277001 | 0.722 ppm |
| 2021-07-06 | 570421001 | 0.729 ppm |
| 2021-07-06 | 570421001 | 0.739 ppm |
| 2021-08-03 | 576276001 | 0.698 ppm |
| 2021-08-03 | 576276001 | 0.744 ppm |
| 2021-09-07 | 582211001 | 0.742 ppm |
| 2021-09-07 | 582211001 | 0.778 ppm |
| 2021-10-12 | 589438001 | 0.688 ppm |
| 2021-10-12 | 589438001 | 0.731 ppm |
| 2021-11-22 | 595716001 | 0.643 ppm |
| 2021-11-22 | 595716001 | 0.716 ppm |
| 2021-12-13 | 598378001 | 0.669 ppm |
| 2021-12-13 | 598378001 | 0.736 ppm |
| 2022-01-18 | 602529001 | 0.742 ppm |
| 2022-01-18 | 602529001 | 0.833 ppm |
| 2022-02-22 | 606742001 | 0.712 ppm |
| 2022-02-22 | 606742001 | 0.775 ppm |
| 2022-03-23 | 610999001 | 0.740 ppm |
| 2022-03-23 | 610999001 | 0.776 ppm |
| 2022-04-19 | 615049001 | 0.725 ppm |
| 2022-04-19 | 615049001 | 0.730 ppm |
| 2022-05-24 | 621558001 | 0.710 ppm |
| 2022-05-24 | 621558001 | 0.794 ppm |
| 2022-06-13 | 624820001 | 0.740 ppm |
| 2022-06-13 | 624820001 | 0.769 ppm |
| 2022-07-18 | 631487001 | 0.691 ppm |
| 2022-07-18 | 631487001 | 0.770 ppm |
| 2022-08-16 | 637538001 | 0.720 ppm |
| 2022-08-16 | 637538001 | 0.725 ppm |
| 2022-09-26 | 644856001 | 0.686 ppm |
| 2022-09-26 | 644856001 | 0.730 ppm |
| 2022-10-04 | 646724001 | 0.685 ppm |
| 2022-10-04 | 646724001 | 0.780 ppm |
| 2022-11-15 | 653589001 | 0.647 ppm |
| 2022-11-15 | 653589001 | 0.700 ppm |
| 2022-12-06 | 656019001 | 0.667 ppm |
| 2022-12-06 | 656019001 | 0.710 ppm |
| 2023-01-03 | 659215001 | 0.631 ppm |
| 2023-01-03 | 659215001 | 0.730 ppm |
| 2023-02-23 | 665793001 | 0.602 ppm |
| 2023-02-23 | 665793001 | 0.690 ppm |
| 2023-03-06 | 666950001 | 0.592 ppm |
| 2023-03-06 | 666950001 | 0.720 ppm |
| 2023-04-12 | 672979001 | 0.750 ppm |
| 2023-04-12 | 672979001 | 0.780 ppm |
| 2023-05-01 | 676043001 | 0.764 ppm |
| 2023-05-01 | 676043001 | 0.780 ppm |
| 2023-05-09 | 23E0327-01 | 0.820 ppm |
| 2023-05-09 | 23E0327-02 | 1.37 ppm |
| 2023-06-13 | 683683001 | 0.761 ppm |
| 2023-06-13 | 683683001 | 0.770 ppm |
| 2023-07-10 | 687705001 | 0.750 ppm |
| 2023-07-10 | 687705001 | 0.782 ppm |
| 2023-08-14 | 694895001 | 0.770 ppm |
| 2023-08-14 | 694895001 | 0.802 ppm |
| 2023-09-21 | 702079001 | 0.697 ppm |
| 2023-09-21 | 702079001 | 0.740 ppm |
| 2023-10-02 | 703968001 | 0.740 ppm |
| 2023-10-02 | 703968001 | 0.788 ppm |
| 2023-11-06 | 709456001 | 0.710 ppm |
| 2023-11-06 | 709456001 | 0.770 ppm |
| 2023-12-05 | 713526001 | 0.730 ppm |
| 2023-12-05 | 713526001 | 0.766 ppm |