Fluoride
Mauston 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 | 0.737 ppm | 24 | 24 | 0.563 ppm - 0.970 ppm |
| 2019 | 0.832 ppm | 24 | 24 | 0.700 ppm - 1.16 ppm |
| 2020 | 0.701 ppm | 23 | 23 | 0.0600 ppm - 0.920 ppm |
| 2021 | 0.779 ppm | 28 | 28 | 0.691 ppm - 0.930 ppm |
| 2022 | 0.745 ppm | 24 | 24 | 0.570 ppm - 0.910 ppm |
| 2023 | 0.674 ppm | 27 | 27 | 0.140 ppm - 0.910 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 | 361979001 | 0.702 ppm |
| 2018-01-08 | 361979001 | 0.790 ppm |
| 2018-02-08 | 366181001 | 0.690 ppm |
| 2018-02-08 | 366181001 | 0.703 ppm |
| 2018-03-21 | 372482001 | 0.734 ppm |
| 2018-03-21 | 372482001 | 0.740 ppm |
| 2018-04-11 | 376099001 | 0.687 ppm |
| 2018-04-11 | 376099001 | 0.810 ppm |
| 2018-05-22 | 384160001 | 0.696 ppm |
| 2018-05-22 | 384160001 | 0.790 ppm |
| 2018-06-06 | 386871001 | 0.702 ppm |
| 2018-06-06 | 386871001 | 0.730 ppm |
| 2018-07-25 | 397007001 | 0.563 ppm |
| 2018-07-25 | 397007001 | 0.620 ppm |
| 2018-08-21 | 402459001 | 0.723 ppm |
| 2018-08-21 | 402459001 | 0.970 ppm |
| 2018-09-25 | 410572001 | 0.650 ppm |
| 2018-09-25 | 410572001 | 0.662 ppm |
| 2018-10-23 | 416180001 | 0.740 ppm |
| 2018-10-23 | 416180001 | 0.762 ppm |
| 2018-11-20 | 420882001 | 0.785 ppm |
| 2018-11-20 | 420882001 | 0.860 ppm |
| 2018-12-18 | 425164001 | 0.717 ppm |
| 2018-12-18 | 425164001 | 0.870 ppm |
| 2019-01-09 | 427260001 | 0.800 ppm |
| 2019-01-09 | 427260001 | 0.870 ppm |
| 2019-02-05 | 430410001 | 0.700 ppm |
| 2019-02-05 | 430410001 | 0.870 ppm |
| 2019-03-19 | 436344001 | 0.779 ppm |
| 2019-03-19 | 436344001 | 0.940 ppm |
| 2019-04-24 | 442406001 | 0.844 ppm |
| 2019-04-24 | 442406001 | 1.16 ppm |
| 2019-05-22 | 447841001 | 0.790 ppm |
| 2019-05-22 | 447841001 | 0.809 ppm |
| 2019-06-19 | 453111001 | 0.820 ppm |
| 2019-06-19 | 453111001 | 0.824 ppm |
| 2019-07-23 | 459427001 | 0.719 ppm |
| 2019-07-23 | 459427001 | 0.760 ppm |
| 2019-08-20 | 465091001 | 0.711 ppm |
| 2019-08-20 | 465091001 | 0.740 ppm |
| 2019-09-10 | 469405001 | 0.700 ppm |
| 2019-09-10 | 469405001 | 0.778 ppm |
| 2019-10-22 | 477860001 | 0.844 ppm |
| 2019-10-22 | 477860001 | 0.850 ppm |
| 2019-11-05 | 480033001 | 0.890 ppm |
| 2019-11-05 | 480033001 | 0.923 ppm |
| 2019-12-03 | 484324001 | 0.910 ppm |
| 2019-12-03 | 484324001 | 0.929 ppm |
| 2020-01-21 | 490323001 | 0.817 ppm |
| 2020-01-21 | 490323001 | 0.920 ppm |
| 2020-04-07 | 500155001 | 0.830 ppm |
| 2020-04-07 | 500155001 | 0.853 ppm |
| 2020-05-05 | 503235001 | 0.880 ppm |
| 2020-05-05 | 503235001 | 0.904 ppm |
| 2020-06-01 | 507408001 | 0.770 ppm |
| 2020-06-01 | 507408001 | 0.800 ppm |
| 2020-07-01 | 512476001 | 0.784 ppm |
| 2020-07-01 | 512476001 | 0.830 ppm |
| 2020-07-16 | 20G0593-02 | 0.0600 ppm |
| 2020-07-16 | 20G0593-01 | 0.0700 ppm |
| 2020-07-16 | 20G0593-03 | 0.0900 ppm |
| 2020-08-04 | 518347001 | 0.690 ppm |
| 2020-08-04 | 518347001 | 0.758 ppm |
| 2020-09-02 | 523425001 | 0.751 ppm |
| 2020-09-02 | 523425001 | 0.850 ppm |
| 2020-10-05 | 529536001 | 0.650 ppm |
| 2020-10-05 | 529536001 | 0.750 ppm |
| 2020-11-04 | 534724001 | 0.774 ppm |
| 2020-11-04 | 534724001 | 0.810 ppm |
| 2020-12-01 | 538085001 | 0.700 ppm |
| 2020-12-01 | 538085001 | 0.779 ppm |
| 2021-01-05 | 542546001 | 0.730 ppm |
| 2021-01-05 | 542546001 | 0.774 ppm |
| 2021-02-03 | 546472001 | 0.771 ppm |
| 2021-02-03 | 546472001 | 0.870 ppm |
| 2021-02-03 | 546472001 | 0.771 ppm |
| 2021-02-03 | 546472001 | 0.870 ppm |
| 2021-03-03 | 550092001 | 0.746 ppm |
| 2021-03-03 | 550092001 | 0.930 ppm |
| 2021-03-03 | 550092001 | 0.746 ppm |
| 2021-03-03 | 550092001 | 0.930 ppm |
| 2021-04-05 | 554589001 | 0.742 ppm |
| 2021-04-05 | 554589001 | 0.850 ppm |
| 2021-05-03 | 559388001 | 0.780 ppm |
| 2021-05-03 | 559388001 | 0.790 ppm |
| 2021-06-01 | 564603001 | 0.751 ppm |
| 2021-06-01 | 564603001 | 0.860 ppm |
| 2021-07-01 | 570178001 | 0.742 ppm |
| 2021-07-01 | 570178001 | 0.810 ppm |
| 2021-08-04 | 576318001 | 0.711 ppm |
| 2021-08-04 | 576318001 | 0.770 ppm |
| 2021-09-08 | 582576001 | 0.713 ppm |
| 2021-09-08 | 582576001 | 0.740 ppm |
| 2021-10-11 | 588782001 | 0.691 ppm |
| 2021-10-11 | 588782001 | 0.730 ppm |
| 2021-11-03 | 592985001 | 0.697 ppm |
| 2021-11-03 | 592985001 | 0.770 ppm |
| 2021-12-06 | 597145001 | 0.745 ppm |
| 2021-12-06 | 597145001 | 0.790 ppm |
| 2022-01-18 | 602525001 | 0.737 ppm |
| 2022-01-18 | 602525001 | 0.850 ppm |
| 2022-02-02 | 604354001 | 0.724 ppm |
| 2022-02-02 | 604354001 | 0.850 ppm |
| 2022-03-01 | 607959001 | 0.728 ppm |
| 2022-03-01 | 607959001 | 0.910 ppm |
| 2022-04-06 | 612811001 | 0.707 ppm |
| 2022-04-06 | 612811001 | 0.760 ppm |
| 2022-05-03 | 617539001 | 0.712 ppm |
| 2022-05-03 | 617539001 | 0.760 ppm |
| 2022-06-06 | 623530001 | 0.687 ppm |
| 2022-06-06 | 623530001 | 0.830 ppm |
| 2022-07-11 | 630349001 | 0.726 ppm |
| 2022-07-11 | 630349001 | 0.740 ppm |
| 2022-08-08 | 635749001 | 0.690 ppm |
| 2022-08-08 | 635749001 | 0.780 ppm |
| 2022-09-07 | 641199001 | 0.570 ppm |
| 2022-09-07 | 641199001 | 0.658 ppm |
| 2022-10-03 | 646492001 | 0.679 ppm |
| 2022-10-03 | 646492001 | 0.740 ppm |
| 2022-11-09 | 652792001 | 0.702 ppm |
| 2022-11-09 | 652792001 | 0.760 ppm |
| 2022-12-06 | 656026001 | 0.715 ppm |
| 2022-12-06 | 656026001 | 0.870 ppm |
| 2023-01-04 | 659442001 | 0.734 ppm |
| 2023-01-04 | 659442001 | 0.910 ppm |
| 2023-02-07 | 663659001 | 0.741 ppm |
| 2023-02-07 | 663659001 | 0.760 ppm |
| 2023-02-28 | 1294258 | 0.140 ppm |
| 2023-02-28 | 1294261 | 0.160 ppm |
| 2023-02-28 | 1294252 | 0.180 ppm |
| 2023-03-07 | 667421001 | 0.723 ppm |
| 2023-03-07 | 667421001 | 0.810 ppm |
| 2023-04-11 | 672780001 | 0.734 ppm |
| 2023-04-11 | 672780001 | 0.820 ppm |
| 2023-05-09 | 677974001 | 0.752 ppm |
| 2023-05-09 | 677974001 | 0.790 ppm |
| 2023-06-06 | 682469001 | 0.680 ppm |
| 2023-06-06 | 682469001 | 0.717 ppm |
| 2023-07-10 | 687713001 | 0.650 ppm |
| 2023-07-10 | 687713001 | 0.729 ppm |
| 2023-08-08 | 693832001 | 0.740 ppm |
| 2023-08-08 | 693832001 | 0.779 ppm |
| 2023-09-05 | 698590001 | 0.710 ppm |
| 2023-09-05 | 698590001 | 0.734 ppm |
| 2023-10-02 | 703960001 | 0.674 ppm |
| 2023-10-02 | 703960001 | 0.690 ppm |
| 2023-11-06 | 709463001 | 0.620 ppm |
| 2023-11-06 | 709463001 | 0.725 ppm |
| 2023-12-04 | 713107001 | 0.728 ppm |
| 2023-12-04 | 713107001 | 0.770 ppm |