Fluoride
Regional Water Authority
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 | 0.262 ppm | 26 | 26 | 0.0300 ppm - 0.790 ppm |
| 2019 | 0.367 ppm | 26 | 26 | 0.0300 ppm - 2.32 ppm |
| 2020 | 0.267 ppm | 25 | 9 | ND - 0.900 ppm |
| 2021 | 0.243 ppm | 29 | 11 | ND - 0.780 ppm |
| 2022 | 0.588 ppm | 136 | 130 | ND - 0.860 ppm |
| 2023 | 0.524 ppm | 15 | 11 | ND - 0.805 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 |
|---|---|---|
| 2018-03-12 | IOCR 200489760 | 0.0400 ppm |
| 2018-03-12 | IOCR 200489758 | 0.0900 ppm |
| 2018-03-12 | IOCR 200489759 | 0.0400 ppm |
| 2018-03-12 | IOCR 200489767 | 0.0400 ppm |
| 2018-03-14 | IOCR 200489911 | 0.0800 ppm |
| 2018-03-14 | IOC1 200489867 | 0.630 ppm |
| 2018-03-14 | IOC1 200489870 | 0.630 ppm |
| 2018-03-14 | IOC1 200489868 | 0.760 ppm |
| 2018-03-14 | IOC1 200489884 | 0.630 ppm |
| 2018-03-14 | IOC1 200489885 | 0.610 ppm |
| 2018-03-14 | IOC1 200489871 | 0.660 ppm |
| 2018-03-14 | IOC1 200489913 | 0.790 ppm |
| 2018-03-14 | IOC1 200489914 | 0.680 ppm |
| 2018-03-14 | IOCR 200489898 | 0.0400 ppm |
| 2018-03-14 | IOCR 200489900 | 0.0500 ppm |
| 2018-03-14 | IOCR 200489896 | 0.0300 ppm |
| 2018-03-14 | IOCR 200489912 | 0.0700 ppm |
| 2018-03-14 | IOCR 200489886 | 0.0500 ppm |
| 2018-03-14 | IOCR 200489887 | 0.0500 ppm |
| 2018-03-14 | IOCR 200489872 | 0.0300 ppm |
| 2018-03-14 | IOCR 200489897 | 0.0400 ppm |
| 2018-03-15 | IOC1 200490061 | 0.570 ppm |
| 2018-03-15 | IOCR 200490062 | 0.0700 ppm |
| 2018-03-15 | IOCR 200490063 | 0.0500 ppm |
| 2018-11-29 | IOC1 200514112 | 0.0600 ppm |
| 2018-11-29 | IOCR 200514114 | 0.0300 ppm |
| 2019-03-18 | IOC1 200524895 | 0.610 ppm |
| 2019-03-18 | IOCR 200524896 | 0.0400 ppm |
| 2019-03-18 | IOCR 200524903 | 0.0500 ppm |
| 2019-03-18 | IOCR 200524901 | 0.0600 ppm |
| 2019-03-18 | IOCR 200524902 | 0.0400 ppm |
| 2019-03-18 | IOCR 200524905 | 0.0400 ppm |
| 2019-03-18 | IOCR 200524900 | 0.0600 ppm |
| 2019-03-19 | IOCR 200525095 | 0.0800 ppm |
| 2019-03-19 | IOC1 200525057 | 0.650 ppm |
| 2019-03-19 | IOC1 200525060 | 0.640 ppm |
| 2019-03-19 | IOC1 200525058 | 0.690 ppm |
| 2019-03-19 | IOC1 200525059 | 0.670 ppm |
| 2019-03-19 | IOC1 200525077 | 0.540 ppm |
| 2019-03-19 | IOC1 200525078 | 0.610 ppm |
| 2019-03-19 | IOC1 200525061 | 0.710 ppm |
| 2019-03-19 | IOC1 200525097 | 0.730 ppm |
| 2019-03-19 | IOC1 200525098 | 0.620 ppm |
| 2019-03-19 | IOCR 200525065 | 0.0300 ppm |
| 2019-03-19 | IOCR 200525066 | 0.0400 ppm |
| 2019-03-19 | IOCR 200525064 | 0.0500 ppm |
| 2019-03-19 | IOCR 200525096 | 0.0900 ppm |
| 2019-03-19 | IOCR 200525079 | 0.0300 ppm |
| 2019-03-19 | IOCR 200525080 | 0.0400 ppm |
| 2019-03-19 | IOCR 200525062 | 0.0500 ppm |
| 2019-05-08 | IOC1 200531297 | 2.32 ppm |
| 2019-05-08 | IOCR 200531303 | 0.0500 ppm |
| 2020-02-10 | IOC1 200565460 | 0.650 ppm |
| 2020-02-10 | IOCR 200565461 | ND |
| 2020-02-10 | IOCR 200565469 | ND |
| 2020-02-10 | IOCR 200565466 | ND |
| 2020-02-10 | IOCR 200565467 | ND |
| 2020-02-10 | IOCR 200565470 | ND |
| 2020-02-11 | IOC1 200565624 | 0.900 ppm |
| 2020-02-11 | IOC1 200565627 | 0.680 ppm |
| 2020-02-11 | IOC1 200565626 | 0.630 ppm |
| 2020-02-11 | IOC1 200565593 | 0.730 ppm |
| 2020-02-11 | IOC1 200565625 | 0.760 ppm |
| 2020-02-11 | IOC1 200565594 | 0.880 ppm |
| 2020-02-11 | IOC1 200565628A | 0.720 ppm |
| 2020-02-11 | IOCR 200565632 | ND |
| 2020-02-11 | IOCR 200565633 | ND |
| 2020-02-11 | IOCR 200565631 | ND |
| 2020-02-11 | IOC1 200565628 | 0.720 ppm |
| 2020-02-11 | IOCR 200565595 | ND |
| 2020-02-11 | IOCR 200565596 | ND |
| 2020-02-11 | IOCR 200565629 | ND |
| 2020-02-12 | IOCR 200565847 | ND |
| 2020-02-12 | IOCR 200565848 | ND |
| 2020-08-10 | IOCR 200585597 | ND |
| 2020-08-11 | IOCR 200585735 | ND |
| 2020-08-11 | IOCR 200585736 | ND |
| 2021-02-08 | IOCR 200605858 | ND |
| 2021-02-08 | IOCR 200605854 | ND |
| 2021-02-08 | IOCR 200605856 | ND |
| 2021-02-08 | IOCR 200605852 | ND |
| 2021-02-08 | IOCR 200605855 | ND |
| 2021-02-09 | IOC1 200606114 | 0.570 ppm |
| 2021-02-09 | IOC1 200606111 | 0.500 ppm |
| 2021-02-09 | IOC1 200606110 | 0.610 ppm |
| 2021-02-09 | IOC1 200606109 | 0.650 ppm |
| 2021-02-09 | IOC1 200605956 | 0.630 ppm |
| 2021-02-09 | IOC1 200605886 | 0.780 ppm |
| 2021-02-09 | IOC1 200605888 | 0.720 ppm |
| 2021-02-09 | IOC1 200606116 | 0.610 ppm |
| 2021-02-09 | IOC1 200605959 | 0.720 ppm |
| 2021-02-09 | IOC1 200605933 | 0.600 ppm |
| 2021-02-09 | IOCR 200606115 | ND |
| 2021-02-09 | IOCR 200606112 | ND |
| 2021-02-09 | IOCR 200606113 | ND |
| 2021-02-09 | IOCR 200605957 | ND |
| 2021-02-09 | IOCR 200605958 | ND |
| 2021-02-09 | IOCR 200605931 | ND |
| 2021-02-09 | IOCR 200605887 | ND |
| 2021-02-09 | IOCR 200605960 | ND |
| 2021-02-09 | IOCR 200605889 | ND |
| 2021-02-09 | IOCR 200606117 | ND |
| 2021-02-10 | IOCR 200606359 | ND |
| 2021-02-10 | IOCR 200606356 | ND |
| 2021-02-17 | IOCR 200606910 | ND |
| 2021-02-17 | IOC1 200606909 | 0.650 ppm |
| 2022-02-01 | E300138473 300138475 | 0.600 ppm |
| 2022-02-01 | E300138468 300138470 | 0.540 ppm |
| 2022-02-01 | E300138463 300138465 | 0.500 ppm |
| 2022-02-01 | E300139124 300139126 | 0.560 ppm |
| 2022-02-01 | E300138212 300138214 | 0.540 ppm |
| 2022-02-01 | E300138222 300138224 | 0.660 ppm |
| 2022-02-01 | E300138478 300138480 | 0.780 ppm |
| 2022-02-01 | E300138489 300138491 | 0.680 ppm |
| 2022-02-02 | E300139291 300139293 | 0.590 ppm |
| 2022-02-02 | E300139288 300139290 | 0.540 ppm |
| 2022-02-02 | E300139285 300139287 | 0.480 ppm |
| 2022-02-02 | E300139632 300139634 | 0.610 ppm |
| 2022-02-02 | E300139092 300139094 | 0.790 ppm |
| 2022-02-02 | E300139095 300139097 | 0.700 ppm |
| 2022-02-02 | E300139297 300139299 | 0.650 ppm |
| 2022-02-02 | E300139311 300139313 | 0.690 ppm |
| 2022-02-03 | E300140006 300140008 | 0.550 ppm |
| 2022-02-03 | E300140003 300140005 | 0.490 ppm |
| 2022-02-03 | E300139786 300139788 | 0.830 ppm |
| 2022-02-03 | E300140026 300140028 | 0.660 ppm |
| 2022-02-03 | E300140018 300140020 | 0.640 ppm |
| 2022-02-04 | E300140160 300140162 | 0.540 ppm |
| 2022-02-04 | E300140157 300140159 | 0.500 ppm |
| 2022-02-04 | E300140154 300140156 | 0.480 ppm |
| 2022-02-04 | E300140151 300140153 | 0.610 ppm |
| 2022-02-04 | E300140145 300140147 | 0.830 ppm |
| 2022-02-04 | E300140148 300140150 | 0.730 ppm |
| 2022-02-04 | E300140142 300140144 | 0.660 ppm |
| 2022-02-04 | E300140139 300140141 | 0.700 ppm |
| 2022-02-07 | E300141157 300141159 | 0.530 ppm |
| 2022-02-07 | E300141166 300141168 | 0.530 ppm |
| 2022-02-07 | E300141160 300141162 | 0.450 ppm |
| 2022-02-07 | E300141163 300141165 | 0.600 ppm |
| 2022-02-07 | E300141145 300141147 | 0.860 ppm |
| 2022-02-07 | E300141148 300141150 | 0.700 ppm |
| 2022-02-07 | E300141169 300141171 | 0.680 ppm |
| 2022-02-07 | E300141207 300141209 | ND |
| 2022-02-08 | E300141653 300141655 | 0.540 ppm |
| 2022-02-08 | E300141648 300141650 | 0.530 ppm |
| 2022-02-08 | E300141643 300141645 | 0.440 ppm |
| 2022-02-08 | E300141638 300141640 | 0.590 ppm |
| 2022-02-08 | E300141595 300141597 | 0.480 ppm |
| 2022-02-08 | E300141960 300141962 | 0.760 ppm |
| 2022-02-08 | E300141970 300141972 | 0.690 ppm |
| 2022-02-08 | E300141661 300141663 | 0.640 ppm |
| 2022-02-08 | E300141669 300141671 | 0.670 ppm |
| 2022-02-09 | E300142548 300142550 | 0.480 ppm |
| 2022-02-09 | E300142545 300142547 | 0.460 ppm |
| 2022-02-09 | E300142542 300142544 | 0.570 ppm |
| 2022-02-09 | E300142722 300142724 | 0.720 ppm |
| 2022-02-09 | E300142557 300142559 | 0.620 ppm |
| 2022-02-09 | E300142571 300142573 | 0.630 ppm |
| 2022-02-10 | E300143103 300143105 | 0.520 ppm |
| 2022-02-10 | E300143100 300143102 | 0.490 ppm |
| 2022-02-10 | E300143403 300143405 | 0.740 ppm |
| 2022-02-10 | E300143409 300143411 | 0.690 ppm |
| 2022-02-10 | E300143126 300143128 | 0.680 ppm |
| 2022-02-10 | E300143118 300143120 | 0.560 ppm |
| 2022-02-11 | E300144356 300144358 | 0.550 ppm |
| 2022-02-11 | E300144353 300144355 | 0.510 ppm |
| 2022-02-11 | E300144347 300144349 | 0.830 ppm |
| 2022-02-11 | E300144350 300144352 | 0.670 ppm |
| 2022-02-11 | E300144344 300144346 | 0.610 ppm |
| 2022-02-11 | E300144341 300144343 | 0.500 ppm |
| 2022-02-14 | E300144715 300144717 | 0.510 ppm |
| 2022-02-14 | E300144703 300144705 | 0.670 ppm |
| 2022-02-14 | E300144845 300144847 | 0.790 ppm |
| 2022-02-14 | E300144850 300144852 | 0.700 ppm |
| 2022-02-15 | E300145541 300145543 | 0.420 ppm |
| 2022-02-15 | E300145532 300145534 | 0.500 ppm |
| 2022-02-15 | E300145523 300145525 | 0.500 ppm |
| 2022-02-15 | E300145514 300145516 | 0.630 ppm |
| 2022-02-15 | E300146276 300146278 | 0.530 ppm |
| 2022-02-15 | E300145647 300145649 | 0.650 ppm |
| 2022-02-15 | E300145667 300145669 | 0.670 ppm |
| 2022-02-15 | E300145550 300145552 | 0.540 ppm |
| 2022-02-15 | E300145575 300145577 | 0.520 ppm |
| 2022-02-15 | E300145699 300145701 | 0.670 ppm |
| 2022-02-15 | E300145718 300145720 | 0.550 ppm |
| 2022-02-15 | I300145657 300145659 | ND |
| 2022-02-15 | I300145585 300145587 | ND |
| 2022-02-15 | I300145677 300145679 | ND |
| 2022-02-15 | I300145560 300145562 | ND |
| 2022-02-16 | E300146580 300146582 | 0.450 ppm |
| 2022-02-16 | E300146577 300146579 | 0.550 ppm |
| 2022-02-16 | E300146421 300146423 | 0.770 ppm |
| 2022-02-16 | E300146444 300146446 | 0.690 ppm |
| 2022-02-16 | E300146595 300146597 | 0.610 ppm |
| 2022-02-16 | E300146606 300146608 | 0.570 ppm |
| 2022-02-17 | E300147156 300147158 | 0.580 ppm |
| 2022-02-17 | E300147153 300147155 | 0.540 ppm |
| 2022-02-17 | E300147022 300147024 | 0.740 ppm |
| 2022-02-17 | E300147028 300147030 | 0.730 ppm |
| 2022-02-17 | E300147183 300147185 | 0.620 ppm |
| 2022-02-17 | E300147205 300147207 | 0.670 ppm |
| 2022-02-18 | E300147715 300147717 | 0.520 ppm |
| 2022-02-18 | E300147712 300147714 | 0.640 ppm |
| 2022-02-18 | E300147709 300147711 | 0.520 ppm |
| 2022-02-18 | E300147845 300147847 | 0.640 ppm |
| 2022-02-18 | E300147703 300147705 | 0.780 ppm |
| 2022-02-18 | E300147706 300147708 | 0.710 ppm |
| 2022-02-18 | E300147700 300147702 | 0.630 ppm |
| 2022-02-18 | E300147697 300147699 | 0.530 ppm |
| 2022-02-22 | E300148542 300148544 | 0.580 ppm |
| 2022-02-22 | E300148537 300148539 | 0.600 ppm |
| 2022-02-22 | E300148528 300148530 | 0.500 ppm |
| 2022-02-22 | E300148523 300148525 | 0.660 ppm |
| 2022-02-22 | E300148248 300148250 | 0.770 ppm |
| 2022-02-22 | E300148258 300148260 | 0.730 ppm |
| 2022-02-22 | E300148550 300148552 | 0.650 ppm |
| 2022-02-22 | E300148703 300148705 | 0.650 ppm |
| 2022-02-23 | E300148780 300148782 | 0.530 ppm |
| 2022-02-23 | E300148777 300148779 | 0.550 ppm |
| 2022-02-23 | E300148774 300148776 | 0.510 ppm |
| 2022-02-23 | E300148771 300148773 | 0.610 ppm |
| 2022-02-23 | E300149000 300149002 | 0.720 ppm |
| 2022-02-23 | E300149003 300149005 | 0.730 ppm |
| 2022-02-23 | E300148783 300148785 | 0.660 ppm |
| 2022-02-23 | E300148791 300148793 | 0.660 ppm |
| 2022-02-24 | E300149334 300149336 | 0.520 ppm |
| 2022-02-24 | E300149331 300149333 | 0.630 ppm |
| 2022-02-24 | E300149328 300149330 | 0.500 ppm |
| 2022-02-24 | E300149325 300149327 | 0.650 ppm |
| 2022-02-24 | E300149675 300149677 | 0.540 ppm |
| 2022-02-24 | E300149536 300149538 | 0.700 ppm |
| 2022-02-24 | E300149542 300149544 | ND |
| 2022-02-24 | E300149351 300149353 | 0.660 ppm |
| 2022-02-24 | E300149343 300149345 | 0.640 ppm |
| 2022-02-28 | E300150035 300150037 | 0.540 ppm |
| 2022-02-28 | E300150295 300150297 | 0.560 ppm |
| 2022-02-28 | E300150038 300150040 | 0.490 ppm |
| 2022-02-28 | E300150041 300150043 | 0.540 ppm |
| 2022-02-28 | E300150283 300150285 | 0.840 ppm |
| 2022-02-28 | E300150286 300150288 | 0.680 ppm |
| 2022-02-28 | E300150044 300150046 | 0.670 ppm |
| 2022-02-28 | E300150071 300150073 | 0.650 ppm |
| 2023-02-06 | E300305466 300305494 | 0.805 ppm |
| 2023-02-06 | E300305519 300305521 | 0.805 ppm |
| 2023-02-07 | E300305797 300305799 | 0.700 ppm |
| 2023-02-07 | I300305807 300305809 | ND |
| 2023-02-14 | E300309461 300309463 | 0.713 ppm |
| 2023-02-14 | E300309762 300309764 | 0.706 ppm |
| 2023-02-14 | E300309452 300309454 | 0.631 ppm |
| 2023-02-14 | E300309097 300309099 | 0.710 ppm |
| 2023-02-14 | E300309470 300309472 | 0.700 ppm |
| 2023-02-14 | E300309495 300309497 | 0.650 ppm |
| 2023-02-14 | E300309531 300309533 | 0.794 ppm |
| 2023-02-14 | E300309550 300309552 | 0.648 ppm |
| 2023-02-14 | I300309505 300309507 | ND |
| 2023-02-14 | I300309107 300309109 | ND |
| 2023-02-14 | I300309480 300309482 | ND |