Fluoride
Spring Green 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 | 0.640 ppm | 24 | 24 | 0.450 ppm - 0.710 ppm |
| 2019 | 0.660 ppm | 24 | 24 | 0.480 ppm - 0.780 ppm |
| 2020 | 0.618 ppm | 22 | 22 | 0.0550 ppm - 0.870 ppm |
| 2021 | 0.682 ppm | 28 | 28 | 0.610 ppm - 0.780 ppm |
| 2022 | 0.761 ppm | 22 | 22 | 0.600 ppm - 1.29 ppm |
| 2023 | 0.784 ppm | 26 | 24 | ND - 1.17 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 |
|---|---|---|
| 2018-01-17 | 363511001 | 0.450 ppm |
| 2018-01-17 | 363511001 | 0.685 ppm |
| 2018-02-21 | 368332001 | 0.620 ppm |
| 2018-02-21 | 368332001 | 0.624 ppm |
| 2018-03-19 | 371915001 | 0.665 ppm |
| 2018-03-19 | 371915001 | 0.690 ppm |
| 2018-04-18 | 377153001 | 0.625 ppm |
| 2018-04-18 | 377153001 | 0.670 ppm |
| 2018-05-21 | 383700001 | 0.680 ppm |
| 2018-05-21 | 383700001 | 0.687 ppm |
| 2018-06-25 | 390895001 | 0.675 ppm |
| 2018-06-25 | 390895001 | 0.690 ppm |
| 2018-07-19 | 395701001 | 0.661 ppm |
| 2018-07-19 | 395701001 | 0.690 ppm |
| 2018-08-22 | 402983001 | 0.663 ppm |
| 2018-08-22 | 402983001 | 0.680 ppm |
| 2018-09-24 | 410033001 | 0.650 ppm |
| 2018-09-24 | 410033001 | 0.677 ppm |
| 2018-10-16 | 415214001 | 0.600 ppm |
| 2018-10-16 | 415214001 | 0.639 ppm |
| 2018-11-15 | 420310001 | 0.493 ppm |
| 2018-11-15 | 420310001 | 0.520 ppm |
| 2018-12-18 | 425166001 | 0.605 ppm |
| 2018-12-18 | 425166001 | 0.710 ppm |
| 2019-01-28 | 429453001 | 0.688 ppm |
| 2019-01-28 | 429453001 | 0.710 ppm |
| 2019-02-25 | 432914001 | 0.560 ppm |
| 2019-02-25 | 432914001 | 0.603 ppm |
| 2019-03-12 | 435215001 | 0.550 ppm |
| 2019-03-12 | 435215001 | 0.617 ppm |
| 2019-04-11 | 440208001 | 0.500 ppm |
| 2019-04-11 | 440208001 | 0.555 ppm |
| 2019-05-13 | 446261001 | 0.480 ppm |
| 2019-05-13 | 446261001 | 0.586 ppm |
| 2019-06-10 | 450988001 | 0.724 ppm |
| 2019-06-10 | 450988001 | 0.780 ppm |
| 2019-07-15 | 458168001 | 0.686 ppm |
| 2019-07-15 | 458168001 | 0.710 ppm |
| 2019-08-12 | 463140001 | 0.703 ppm |
| 2019-08-12 | 463140001 | 0.710 ppm |
| 2019-09-09 | 468738001 | 0.680 ppm |
| 2019-09-09 | 468738001 | 0.780 ppm |
| 2019-10-09 | 475742001 | 0.673 ppm |
| 2019-10-09 | 475742001 | 0.760 ppm |
| 2019-11-13 | 481546001 | 0.686 ppm |
| 2019-11-13 | 481546001 | 0.740 ppm |
| 2019-12-11 | 485703001 | 0.674 ppm |
| 2019-12-11 | 485703001 | 0.690 ppm |
| 2020-01-14 | 489543001 | 0.683 ppm |
| 2020-01-14 | 489543001 | 0.870 ppm |
| 2020-04-14 | 501000001 | 0.691 ppm |
| 2020-04-14 | 501000001 | 0.720 ppm |
| 2020-04-15 | 1183334 | 0.0550 ppm |
| 2020-04-15 | 1183337 | 0.0800 ppm |
| 2020-05-19 | 505756001 | 0.690 ppm |
| 2020-05-19 | 505756001 | 0.691 ppm |
| 2020-06-09 | 509021001 | 0.691 ppm |
| 2020-06-09 | 509021001 | 0.700 ppm |
| 2020-07-15 | 515146001 | 0.676 ppm |
| 2020-07-15 | 515146001 | 0.710 ppm |
| 2020-08-10 | 519278001 | 0.630 ppm |
| 2020-08-10 | 519278001 | 0.687 ppm |
| 2020-09-14 | 525764001 | 0.540 ppm |
| 2020-09-14 | 525764001 | 0.688 ppm |
| 2020-10-13 | 531123001 | 0.520 ppm |
| 2020-10-13 | 531123001 | 0.672 ppm |
| 2020-11-10 | 535619001 | 0.530 ppm |
| 2020-11-10 | 535619001 | 0.671 ppm |
| 2020-12-15 | 540587001 | 0.645 ppm |
| 2020-12-15 | 540587001 | 0.760 ppm |
| 2021-01-12 | 543517001 | 0.656 ppm |
| 2021-01-12 | 543517001 | 0.730 ppm |
| 2021-02-23 | 548833001 | 0.675 ppm |
| 2021-02-23 | 548833001 | 0.700 ppm |
| 2021-02-23 | 548833001 | 0.675 ppm |
| 2021-02-23 | 548833001 | 0.700 ppm |
| 2021-03-08 | 550752001 | 0.700 ppm |
| 2021-03-08 | 550752001 | 0.710 ppm |
| 2021-03-08 | 550752001 | 0.700 ppm |
| 2021-03-08 | 550752001 | 0.710 ppm |
| 2021-04-20 | 557392001 | 0.651 ppm |
| 2021-04-20 | 557392001 | 0.700 ppm |
| 2021-05-24 | 563410001 | 0.610 ppm |
| 2021-05-24 | 563410001 | 0.708 ppm |
| 2021-06-28 | 569345001 | 0.691 ppm |
| 2021-06-28 | 569345001 | 0.780 ppm |
| 2021-07-26 | 574426001 | 0.648 ppm |
| 2021-07-26 | 574426001 | 0.680 ppm |
| 2021-08-30 | 580958001 | 0.610 ppm |
| 2021-08-30 | 580958001 | 0.720 ppm |
| 2021-09-28 | 586616001 | 0.620 ppm |
| 2021-09-28 | 586616001 | 0.627 ppm |
| 2021-10-25 | 591377001 | 0.643 ppm |
| 2021-10-25 | 591377001 | 0.670 ppm |
| 2021-11-17 | 595276001 | 0.623 ppm |
| 2021-11-17 | 595276001 | 0.690 ppm |
| 2021-12-21 | 599696001 | 0.690 ppm |
| 2021-12-21 | 599696001 | 0.780 ppm |
| 2022-01-27 | 603568001 | 0.660 ppm |
| 2022-01-27 | 603568001 | 0.819 ppm |
| 2022-02-21 | 606696001 | 0.700 ppm |
| 2022-02-21 | 606696001 | 0.830 ppm |
| 2022-03-23 | 611025001 | 0.780 ppm |
| 2022-03-23 | 611025001 | 0.848 ppm |
| 2022-04-27 | 616230001 | 0.800 ppm |
| 2022-04-27 | 616230001 | 0.884 ppm |
| 2022-05-25 | 621862001 | 0.900 ppm |
| 2022-05-25 | 621862001 | 1.29 ppm |
| 2022-06-29 | 627876001 | 0.640 ppm |
| 2022-06-29 | 627876001 | 0.644 ppm |
| 2022-07-27 | 633659001 | 0.640 ppm |
| 2022-07-27 | 633659001 | 0.756 ppm |
| 2022-08-29 | 639542001 | 0.600 ppm |
| 2022-08-29 | 639542001 | 0.738 ppm |
| 2022-09-27 | 645360001 | 0.660 ppm |
| 2022-09-27 | 645360001 | 0.698 ppm |
| 2022-10-31 | 651519001 | 0.690 ppm |
| 2022-10-31 | 651519001 | 0.711 ppm |
| 2022-12-14 | 657549001 | 0.680 ppm |
| 2022-12-14 | 657549001 | 0.770 ppm |
| 2023-01-11 | 660479001 | 0.640 ppm |
| 2023-01-11 | 660479001 | 0.744 ppm |
| 2023-02-15 | 664944001 | 0.650 ppm |
| 2023-02-15 | 664944001 | 0.740 ppm |
| 2023-03-16 | 668836001 | 0.700 ppm |
| 2023-03-16 | 668836001 | 0.756 ppm |
| 2023-03-28 | 1304000 | ND |
| 2023-03-28 | 1304002 | ND |
| 2023-04-25 | 675113001 | 0.730 ppm |
| 2023-04-25 | 675113001 | 0.888 ppm |
| 2023-05-30 | 681119001 | 0.910 ppm |
| 2023-05-30 | 681119001 | 1.13 ppm |
| 2023-06-27 | 686085001 | 0.600 ppm |
| 2023-06-27 | 686085001 | 0.835 ppm |
| 2023-07-21 | 690595001 | 0.660 ppm |
| 2023-07-21 | 690595001 | 1.17 ppm |
| 2023-08-22 | 696560001 | 0.950 ppm |
| 2023-08-22 | 696560001 | 1.08 ppm |
| 2023-09-21 | 702080001 | 0.840 ppm |
| 2023-09-21 | 702080001 | 1.03 ppm |
| 2023-10-26 | 708153001 | 0.800 ppm |
| 2023-10-26 | 708153001 | 0.951 ppm |
| 2023-11-29 | 712602001 | 0.840 ppm |
| 2023-11-29 | 712602001 | 0.899 ppm |
| 2023-12-27 | 716112001 | 0.910 ppm |
| 2023-12-27 | 716112001 | 0.940 ppm |