Fluoride
Regional Water Authority
Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems. Read More.
Fluoride has been promoted as a chemical that reduces dental cavities. Yet it is now well-established that fluoride primarily exerts its protective effects through topical mechanisms, such as sodium fluoride in toothpaste and mouthwash. In contrast, long-term ingestion of fluoride in water increases dental fluorosis, which includes mottling, pitting and weakening of the teeth. 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 fractures, although these effects may occur at lower doses.
Even fluoride levels of 0.7 ppm, the amount of fluoride in drinking water recommended by the U.S. Public Health Service, can result in too much fluoride for bottle-fed babies. EWG recommends that caregivers mix baby formula with fluoride-free water. The National Toxicology Program is investigating the potential for low doses of fluoride to alter thyroid function and childhood brain development.
155
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.402 ppm | 25 | 25 | 0.0300 ppm - 1.09 ppm |
| 2015 | 0.390 ppm | 25 | 25 | 0.0300 ppm - 1.02 ppm |
| 2016 | 0.412 ppm | 26 | 26 | 0.0300 ppm - 1.14 ppm |
| 2017 | 0.303 ppm | 27 | 27 | 0.0300 ppm - 0.830 ppm |
| 2018 | 0.262 ppm | 26 | 26 | 0.0300 ppm - 0.790 ppm |
| 2019 | 0.367 ppm | 26 | 26 | 0.0300 ppm - 2.32 ppm |
ppm = parts per million
State and national drinking water standards and health guidelines
EPA Maximum Contaminant
Level (MCL) 4 ppm
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2014-02-24 | IOCR 200391476 | 0.0500 ppm |
| 2014-02-24 | IOCR 200391478 | 0.0400 ppm |
| 2014-02-24 | IOCR 200391480 | 0.0600 ppm |
| 2014-02-24 | IOCR 200391481 | 0.0400 ppm |
| 2014-02-24 | IOCR 200391482 | 0.0400 ppm |
| 2014-02-25 | IOC1 200391599 | 0.790 ppm |
| 2014-02-25 | IOC1 200391600 | 0.870 ppm |
| 2014-02-25 | IOC1 200391616 | 0.970 ppm |
| 2014-02-25 | IOC1 200391617 | 1.02 ppm |
| 2014-02-25 | IOC1 200391618 | 0.990 ppm |
| 2014-02-25 | IOC1 200391619 | 0.920 ppm |
| 2014-02-25 | IOC1 200391620 | 0.970 ppm |
| 2014-02-25 | IOC1 200391653 | 0.840 ppm |
| 2014-02-25 | IOCR 200391602 | 0.0300 ppm |
| 2014-02-25 | IOCR 200391603 | 0.0400 ppm |
| 2014-02-25 | IOCR 200391621 | 0.0300 ppm |
| 2014-02-25 | IOCR 200391624 | 0.0400 ppm |
| 2014-02-25 | IOCR 200391625 | 0.0400 ppm |
| 2014-02-26 | IOCR 200391727 | 0.0400 ppm |
| 2014-03-18 | IOCR 200392806 | 0.0500 ppm |
| 2014-05-13 | IOC1 200395855 | 1.09 ppm |
| 2014-05-13 | IOC1 200395860 | 0.910 ppm |
| 2014-05-13 | IOCR 200395856 | 0.0500 ppm |
| 2014-05-13 | IOCR 200395862 | 0.0700 ppm |
| 2014-05-13 | IOCR 200395863 | 0.0700 ppm |
| 2015-02-09 | IOCR 200411809 | 0.0500 ppm |
| 2015-02-09 | IOCR 200411814 | 0.0600 ppm |
| 2015-02-09 | IOCR 200411810 | 0.0400 ppm |
| 2015-02-09 | IOCR 200411811 | 0.0500 ppm |
| 2015-02-09 | IOCR 200411812 | 0.0800 ppm |
| 2015-02-10 | IOCR 200411877 | 0.0700 ppm |
| 2015-02-10 | IOC1 200411859 | 0.950 ppm |
| 2015-02-10 | IOC1 200411862 | 0.870 ppm |
| 2015-02-10 | IOC1 200411860 | 0.850 ppm |
| 2015-02-10 | IOC1 200411845 | 0.910 ppm |
| 2015-02-10 | IOC1 200411846 | 0.910 ppm |
| 2015-02-10 | IOC1 200411863 | 0.970 ppm |
| 2015-02-10 | IOC1 200411876 | 0.810 ppm |
| 2015-02-10 | IOCR 200411867 | 0.0500 ppm |
| 2015-02-10 | IOCR 200411866 | 0.0500 ppm |
| 2015-02-10 | IOCR 200411847 | 0.0400 ppm |
| 2015-02-10 | IOCR 200411848 | 0.0600 ppm |
| 2015-02-10 | IOCR 200411864 | 0.0400 ppm |
| 2015-02-11 | IOCR 200411985 | 0.0400 ppm |
| 2015-05-04 | IOCR 200415956 | 0.0300 ppm |
| 2015-05-05 | IOC1 200416148 | 1.02 ppm |
| 2015-05-05 | IOC1 200416175 | 0.860 ppm |
| 2015-05-05 | IOC1 200416168 | 0.840 ppm |
| 2015-05-05 | IOCR 200416169 | 0.0600 ppm |
| 2015-06-05 | IOCR 200417825 | 0.0400 ppm |
| 2016-02-08 | IOCR 200433335 | 0.0500 ppm |
| 2016-02-08 | IOCR 200433340 | 0.0400 ppm |
| 2016-02-08 | IOCR 200433341 | 0.0400 ppm |
| 2016-02-08 | IOCR 200433336 | 0.0400 ppm |
| 2016-02-08 | IOCR 200433338 | 0.0700 ppm |
| 2016-02-09 | IOCR 200433424 | 0.0600 ppm |
| 2016-02-09 | IOC1 200433411 | 1.03 ppm |
| 2016-02-09 | IOC1 200433414 | 1.13 ppm |
| 2016-02-09 | IOC1 200433412 | 1.05 ppm |
| 2016-02-09 | IOC1 200433413 | 0.930 ppm |
| 2016-02-09 | IOC1 200433479 | 1.14 ppm |
| 2016-02-09 | IOC1 200433397 | 0.860 ppm |
| 2016-02-09 | IOC1 200433398 | 0.880 ppm |
| 2016-02-09 | IOC1 200433415 | 0.880 ppm |
| 2016-02-09 | IOC1 200433425 | 0.920 ppm |
| 2016-02-09 | IOCR 200433420 | 0.0500 ppm |
| 2016-02-09 | IOCR 200433419 | 0.0400 ppm |
| 2016-02-09 | IOCR 200433418 | 0.0400 ppm |
| 2016-02-09 | IOCR 200433480 | 0.0400 ppm |
| 2016-02-09 | IOCR 200433399 | 0.0300 ppm |
| 2016-02-09 | IOCR 200433400 | 0.0500 ppm |
| 2016-02-09 | IOCR 200433416 | 0.0500 ppm |
| 2016-02-10 | IOCR 200433549 | 0.0500 ppm |
| 2016-05-12 | IOC1 200439513 | 1.10 ppm |
| 2016-05-12 | IOCR 200439514 | 0.0300 ppm |
| 2016-11-22 | IOCR 200455269 | 0.120 ppm |
| 2017-03-20 | IOCR 200462640 | 0.0700 ppm |
| 2017-03-20 | IOCR 200462646 | 0.0500 ppm |
| 2017-03-20 | IOCR 200462641 | 0.0400 ppm |
| 2017-03-20 | IOCR 200462642 | 0.0400 ppm |
| 2017-03-20 | IOCR 200462645 | 0.0400 ppm |
| 2017-03-21 | IOCR 200462775 | 0.0600 ppm |
| 2017-03-21 | IOC1 200462739 | 0.670 ppm |
| 2017-03-21 | IOC1 200462742 | 0.720 ppm |
| 2017-03-21 | IOC1 200462740 | 0.650 ppm |
| 2017-03-21 | IOC1 200462741 | 0.720 ppm |
| 2017-03-21 | IOC1 200462793 | 0.680 ppm |
| 2017-03-21 | IOC1 200462756 | 0.600 ppm |
| 2017-03-21 | IOC1 200462757 | 0.650 ppm |
| 2017-03-21 | IOC1 200462743 | 0.590 ppm |
| 2017-03-21 | IOC1 200462777 | 0.590 ppm |
| 2017-03-21 | IOCR 200462833 | 0.0300 ppm |
| 2017-03-21 | IOCR 200462764 | 0.0600 ppm |
| 2017-03-21 | IOCR 200462794 | 0.0500 ppm |
| 2017-03-21 | IOCR 200462795 | 0.0300 ppm |
| 2017-03-21 | IOCR 200462758 | 0.0300 ppm |
| 2017-03-21 | IOCR 200462759 | 0.0600 ppm |
| 2017-03-21 | IOCR 200462744 | 0.0300 ppm |
| 2017-06-19 | IOCR 200469686 | 0.0400 ppm |
| 2017-06-20 | IOC1 200469812 | 0.730 ppm |
| 2017-06-20 | IOC1 200469827 | 0.830 ppm |
| 2017-06-20 | IOCR 200469828 | 0.0700 ppm |
| 2017-06-20 | IOCR 200469813 | 0.0400 ppm |
| 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 |