Fluoride
Deforest 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 | 0.784 ppm | 24 | 24 | 0.600 ppm - 1.10 ppm |
| 2019 | 0.708 ppm | 24 | 24 | 0.0700 ppm - 0.800 ppm |
| 2020 | 0.598 ppm | 25 | 25 | 0.1000 ppm - 0.800 ppm |
| 2021 | 0.707 ppm | 28 | 28 | 0.600 ppm - 0.800 ppm |
| 2022 | 0.688 ppm | 24 | 24 | 0.600 ppm - 0.752 ppm |
| 2023 | 0.575 ppm | 28 | 28 | 0.1000 ppm - 0.800 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 |
|---|---|---|
| 2018-01-02 | 360958001 | 0.828 ppm |
| 2018-01-02 | 360958001 | 0.900 ppm |
| 2018-02-05 | 365274001 | 0.790 ppm |
| 2018-02-05 | 365274001 | 0.800 ppm |
| 2018-03-05 | 369206001 | 0.766 ppm |
| 2018-03-05 | 369206001 | 1.000 ppm |
| 2018-04-03 | 374171001 | 0.726 ppm |
| 2018-04-03 | 374171001 | 1.10 ppm |
| 2018-05-01 | 378992001 | 0.783 ppm |
| 2018-05-01 | 378992001 | 0.800 ppm |
| 2018-06-06 | 386717001 | 0.739 ppm |
| 2018-06-06 | 386717001 | 0.800 ppm |
| 2018-07-16 | 394407001 | 0.600 ppm |
| 2018-07-16 | 394407001 | 0.758 ppm |
| 2018-08-07 | 399167001 | 0.650 ppm |
| 2018-08-07 | 399167001 | 0.750 ppm |
| 2018-09-18 | 408523001 | 0.662 ppm |
| 2018-09-18 | 408523001 | 0.740 ppm |
| 2018-10-01 | 411355001 | 0.723 ppm |
| 2018-10-01 | 411355001 | 0.800 ppm |
| 2018-11-05 | 417567001 | 0.721 ppm |
| 2018-11-05 | 417567001 | 0.800 ppm |
| 2018-12-03 | 421901001 | 0.769 ppm |
| 2018-12-03 | 421901001 | 0.800 ppm |
| 2019-01-07 | 426192001 | 0.767 ppm |
| 2019-01-07 | 426192001 | 0.800 ppm |
| 2019-02-04 | 429665001 | 0.752 ppm |
| 2019-02-04 | 429665001 | 0.800 ppm |
| 2019-03-04 | 433363001 | 0.600 ppm |
| 2019-03-04 | 433363001 | 0.720 ppm |
| 2019-04-01 | 437778001 | 0.700 ppm |
| 2019-04-01 | 437778001 | 0.721 ppm |
| 2019-05-08 | 444794001 | 0.685 ppm |
| 2019-05-08 | 444794001 | 0.700 ppm |
| 2019-06-03 | 448968001 | 0.718 ppm |
| 2019-06-03 | 448968001 | 0.800 ppm |
| 2019-07-02 | 455194001 | 0.715 ppm |
| 2019-07-02 | 455194001 | 0.800 ppm |
| 2019-08-05 | 461137001 | 0.0700 ppm |
| 2019-08-05 | 461137001 | 0.725 ppm |
| 2019-09-09 | 468110001 | 0.724 ppm |
| 2019-09-09 | 468110001 | 0.800 ppm |
| 2019-10-08 | 475047001 | 0.686 ppm |
| 2019-10-08 | 475047001 | 0.700 ppm |
| 2019-11-05 | 479649001 | 0.708 ppm |
| 2019-11-05 | 479649001 | 0.750 ppm |
| 2019-12-02 | 483649001 | 0.740 ppm |
| 2019-12-02 | 483649001 | 0.800 ppm |
| 2020-01-06 | 487739001 | 0.700 ppm |
| 2020-01-06 | 487739001 | 0.745 ppm |
| 2020-04-01 | 499159001 | 0.729 ppm |
| 2020-04-01 | 499159001 | 0.800 ppm |
| 2020-04-22 | 1184622 | 0.1000 ppm |
| 2020-04-22 | 1184622 | 0.1000 ppm |
| 2020-04-22 | 1184626 | 0.1000 ppm |
| 2020-04-22 | 1184624 | 0.1000 ppm |
| 2020-04-22 | 1184625 | 0.120 ppm |
| 2020-05-06 | 503501001 | 0.600 ppm |
| 2020-05-06 | 503501001 | 0.787 ppm |
| 2020-06-01 | 506960001 | 0.700 ppm |
| 2020-06-01 | 506960001 | 0.718 ppm |
| 2020-07-08 | 513519001 | 0.694 ppm |
| 2020-07-08 | 513519001 | 0.800 ppm |
| 2020-08-04 | 518086001 | 0.668 ppm |
| 2020-08-04 | 518086001 | 0.700 ppm |
| 2020-09-09 | 524282001 | 0.688 ppm |
| 2020-09-09 | 524282001 | 0.800 ppm |
| 2020-10-05 | 529056001 | 0.678 ppm |
| 2020-10-05 | 529056001 | 0.700 ppm |
| 2020-11-02 | 533945001 | 0.681 ppm |
| 2020-11-02 | 533945001 | 0.800 ppm |
| 2020-12-01 | 537857001 | 0.708 ppm |
| 2020-12-01 | 537857001 | 0.730 ppm |
| 2021-01-05 | 542207001 | 0.747 ppm |
| 2021-01-05 | 542207001 | 0.800 ppm |
| 2021-02-08 | 546620001 | 0.797 ppm |
| 2021-02-08 | 546620001 | 0.800 ppm |
| 2021-02-08 | 546620001 | 0.797 ppm |
| 2021-02-08 | 546620001 | 0.800 ppm |
| 2021-03-01 | 549191001 | 0.753 ppm |
| 2021-03-01 | 549191001 | 0.800 ppm |
| 2021-03-01 | 549191001 | 0.753 ppm |
| 2021-03-01 | 549191001 | 0.800 ppm |
| 2021-04-08 | 555224001 | 0.650 ppm |
| 2021-04-08 | 555224001 | 0.704 ppm |
| 2021-05-03 | 559225001 | 0.600 ppm |
| 2021-05-03 | 559225001 | 0.713 ppm |
| 2021-06-02 | 564669001 | 0.700 ppm |
| 2021-06-02 | 564669001 | 0.705 ppm |
| 2021-07-15 | 572598001 | 0.670 ppm |
| 2021-07-15 | 572598001 | 0.700 ppm |
| 2021-08-02 | 575431001 | 0.681 ppm |
| 2021-08-02 | 575431001 | 0.700 ppm |
| 2021-09-09 | 582559001 | 0.600 ppm |
| 2021-09-09 | 582559001 | 0.625 ppm |
| 2021-10-05 | 587762001 | 0.600 ppm |
| 2021-10-05 | 587762001 | 0.639 ppm |
| 2021-11-03 | 592880001 | 0.656 ppm |
| 2021-11-03 | 592880001 | 0.700 ppm |
| 2021-12-01 | 596408001 | 0.605 ppm |
| 2021-12-01 | 596408001 | 0.700 ppm |
| 2022-01-10 | 601140001 | 0.700 ppm |
| 2022-01-10 | 601140001 | 0.752 ppm |
| 2022-02-03 | 604424001 | 0.697 ppm |
| 2022-02-03 | 604424001 | 0.700 ppm |
| 2022-03-02 | 607757001 | 0.700 ppm |
| 2022-03-02 | 607757001 | 0.751 ppm |
| 2022-04-06 | 612738001 | 0.700 ppm |
| 2022-04-06 | 612738001 | 0.741 ppm |
| 2022-05-03 | 617075001 | 0.700 ppm |
| 2022-05-03 | 617075001 | 0.703 ppm |
| 2022-06-06 | 623085001 | 0.661 ppm |
| 2022-06-06 | 623085001 | 0.700 ppm |
| 2022-07-14 | 630764001 | 0.700 ppm |
| 2022-07-14 | 630764001 | 0.713 ppm |
| 2022-08-03 | 634785001 | 0.689 ppm |
| 2022-08-03 | 634785001 | 0.700 ppm |
| 2022-09-07 | 640987001 | 0.600 ppm |
| 2022-09-07 | 640987001 | 0.628 ppm |
| 2022-10-03 | 646004001 | 0.666 ppm |
| 2022-10-03 | 646004001 | 0.700 ppm |
| 2022-11-01 | 650986001 | 0.650 ppm |
| 2022-11-01 | 650986001 | 0.691 ppm |
| 2022-12-07 | 656222001 | 0.600 ppm |
| 2022-12-07 | 656222001 | 0.678 ppm |
| 2023-01-10 | 660090001 | 0.700 ppm |
| 2023-01-10 | 660090001 | 0.758 ppm |
| 2023-02-06 | 663151001 | 0.674 ppm |
| 2023-02-06 | 663151001 | 0.700 ppm |
| 2023-03-06 | 666784001 | 0.700 ppm |
| 2023-03-06 | 666784001 | 0.754 ppm |
| 2023-04-19 | 673986001 | 0.500 ppm |
| 2023-04-19 | 673986001 | 0.546 ppm |
| 2023-05-08 | 677141001 | 0.596 ppm |
| 2023-05-08 | 677141001 | 0.600 ppm |
| 2023-06-06 | 682095001 | 0.500 ppm |
| 2023-06-06 | 682095001 | 0.620 ppm |
| 2023-07-10 | 687525001 | 0.680 ppm |
| 2023-07-10 | 687525001 | 0.700 ppm |
| 2023-08-10 | 694200001 | 0.608 ppm |
| 2023-08-10 | 694200001 | 0.700 ppm |
| 2023-08-23 | 696682001 | 0.1000 ppm |
| 2023-08-23 | 696679001 | 0.105 ppm |
| 2023-08-23 | 696680001 | 0.110 ppm |
| 2023-08-23 | 696684001 | 0.124 ppm |
| 2023-09-07 | 698952001 | 0.623 ppm |
| 2023-09-07 | 698952001 | 0.700 ppm |
| 2023-10-03 | 704068001 | 0.572 ppm |
| 2023-10-03 | 704068001 | 0.600 ppm |
| 2023-11-08 | 709978001 | 0.666 ppm |
| 2023-11-08 | 709978001 | 0.800 ppm |
| 2023-12-20 | 715681001 | 0.665 ppm |
| 2023-12-20 | 715681001 | 0.700 ppm |