Fluoride
Middleton Waterworks
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.
Samples
Samples exceeding legal limit (MCL)
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.766 ppm | 30 | 30 | 0.0730 ppm - 1.000 ppm |
| 2015 | 0.816 ppm | 24 | 24 | 0.774 ppm - 0.850 ppm |
| 2016 | 0.809 ppm | 24 | 24 | 0.754 ppm - 0.854 ppm |
| 2017 | 0.759 ppm | 30 | 30 | 0.0910 ppm - 0.877 ppm |
| 2018 | 0.848 ppm | 24 | 24 | 0.800 ppm - 0.917 ppm |
| 2019 | 0.849 ppm | 24 | 24 | 0.774 ppm - 0.948 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 |
|---|---|---|
| 2014-01-13 | 115667001 | 0.781 ppm |
| 2014-01-13 | 115667001 | 0.830 ppm |
| 2014-02-13 | 119680001 | 0.796 ppm |
| 2014-02-13 | 119680001 | 0.820 ppm |
| 2014-03-04 | 121692001 | 0.805 ppm |
| 2014-03-04 | 121692001 | 0.830 ppm |
| 2014-04-14 | 127367001 | 0.790 ppm |
| 2014-04-14 | 127367001 | 0.800 ppm |
| 2014-04-24 | 782320 | 0.770 ppm |
| 2014-04-24 | 782323 | 0.770 ppm |
| 2014-05-08 | 131422001 | 0.780 ppm |
| 2014-05-08 | 131422001 | 0.880 ppm |
| 2014-05-19 | 790003 | 0.0730 ppm |
| 2014-05-19 | 790000 | 0.0980 ppm |
| 2014-06-03 | 793962 | 0.750 ppm |
| 2014-06-03 | 793964 | 1.000 ppm |
| 2014-06-16 | 139084001 | 0.800 ppm |
| 2014-06-16 | 139084001 | 0.807 ppm |
| 2014-07-21 | 146313001 | 0.790 ppm |
| 2014-07-21 | 146313001 | 0.808 ppm |
| 2014-08-19 | 152197001 | 0.761 ppm |
| 2014-08-19 | 152197001 | 0.860 ppm |
| 2014-09-09 | 155751001 | 0.784 ppm |
| 2014-09-09 | 155751001 | 0.800 ppm |
| 2014-10-02 | 161232001 | 0.797 ppm |
| 2014-10-02 | 161232001 | 0.870 ppm |
| 2014-11-19 | 169361001 | 0.809 ppm |
| 2014-11-19 | 169361001 | 0.840 ppm |
| 2014-12-02 | 170536001 | 0.828 ppm |
| 2014-12-02 | 170536001 | 0.850 ppm |
| 2015-01-08 | 174927001 | 0.835 ppm |
| 2015-01-08 | 174927001 | 0.840 ppm |
| 2015-02-03 | 177992001 | 0.826 ppm |
| 2015-02-03 | 177992001 | 0.840 ppm |
| 2015-03-25 | 185041001 | 0.802 ppm |
| 2015-03-25 | 185041001 | 0.820 ppm |
| 2015-04-09 | 187202001 | 0.800 ppm |
| 2015-04-09 | 187202001 | 0.811 ppm |
| 2015-05-05 | 191313001 | 0.833 ppm |
| 2015-05-05 | 191313001 | 0.840 ppm |
| 2015-06-09 | 198374001 | 0.804 ppm |
| 2015-06-09 | 198374001 | 0.850 ppm |
| 2015-07-24 | 207803001 | 0.802 ppm |
| 2015-07-24 | 207803001 | 0.830 ppm |
| 2015-08-17 | 211956001 | 0.790 ppm |
| 2015-08-17 | 211956001 | 0.800 ppm |
| 2015-09-10 | 216617001 | 0.774 ppm |
| 2015-09-10 | 216617001 | 0.800 ppm |
| 2015-10-08 | 222801001 | 0.776 ppm |
| 2015-10-08 | 222801001 | 0.830 ppm |
| 2015-11-13 | 228462001 | 0.790 ppm |
| 2015-11-13 | 228462001 | 0.840 ppm |
| 2015-12-03 | 230994001 | 0.800 ppm |
| 2015-12-03 | 230994001 | 0.840 ppm |
| 2016-01-13 | 235729001 | 0.820 ppm |
| 2016-01-13 | 235729001 | 0.854 ppm |
| 2016-02-09 | 238880001 | 0.800 ppm |
| 2016-02-09 | 238880001 | 0.823 ppm |
| 2016-03-24 | 245565001 | 0.830 ppm |
| 2016-03-24 | 245565001 | 0.842 ppm |
| 2016-04-12 | 248129001 | 0.786 ppm |
| 2016-04-12 | 248129001 | 0.820 ppm |
| 2016-05-24 | 256703001 | 0.816 ppm |
| 2016-05-24 | 256703001 | 0.830 ppm |
| 2016-06-13 | 260941001 | 0.785 ppm |
| 2016-06-13 | 260941001 | 0.820 ppm |
| 2016-07-06 | 264299001 | 0.796 ppm |
| 2016-07-06 | 264299001 | 0.830 ppm |
| 2016-08-08 | 270616001 | 0.758 ppm |
| 2016-08-08 | 270616001 | 0.820 ppm |
| 2016-09-21 | 279304001 | 0.754 ppm |
| 2016-09-21 | 279304001 | 0.800 ppm |
| 2016-10-26 | 286012001 | 0.800 ppm |
| 2016-10-26 | 286012001 | 0.834 ppm |
| 2016-11-11 | 288622001 | 0.781 ppm |
| 2016-11-11 | 288622001 | 0.800 ppm |
| 2016-12-14 | 293115001 | 0.784 ppm |
| 2016-12-14 | 293115001 | 0.840 ppm |
| 2017-01-20 | 296931001 | 0.848 ppm |
| 2017-01-20 | 296931001 | 0.850 ppm |
| 2017-02-07 | 298927001 | 0.810 ppm |
| 2017-02-07 | 298927001 | 0.877 ppm |
| 2017-03-01 | 301968001 | 0.777 ppm |
| 2017-03-01 | 301968001 | 0.820 ppm |
| 2017-04-05 | 308049001 | 0.814 ppm |
| 2017-04-05 | 308049001 | 0.820 ppm |
| 2017-05-04 | 313770001 | 0.830 ppm |
| 2017-05-04 | 313770001 | 0.834 ppm |
| 2017-05-17 | 990973 | 0.0910 ppm |
| 2017-05-17 | 990977 | 0.720 ppm |
| 2017-05-24 | 993617 | 0.830 ppm |
| 2017-06-05 | 995323 | 0.110 ppm |
| 2017-06-19 | 998505 | 0.430 ppm |
| 2017-06-19 | 998508 | 0.800 ppm |
| 2017-06-20 | 322974001 | 0.763 ppm |
| 2017-06-20 | 322974001 | 0.800 ppm |
| 2017-07-05 | 325891001 | 0.800 ppm |
| 2017-07-05 | 325891001 | 0.821 ppm |
| 2017-08-16 | 336293001 | 0.801 ppm |
| 2017-08-16 | 336293001 | 0.850 ppm |
| 2017-09-06 | 340115001 | 0.800 ppm |
| 2017-09-06 | 340115001 | 0.875 ppm |
| 2017-10-09 | 347515001 | 0.800 ppm |
| 2017-10-09 | 347515001 | 0.844 ppm |
| 2017-11-16 | 354997001 | 0.820 ppm |
| 2017-11-16 | 354997001 | 0.855 ppm |
| 2017-12-04 | 356955001 | 0.820 ppm |
| 2017-12-04 | 356955001 | 0.860 ppm |
| 2018-01-04 | 361315001 | 0.840 ppm |
| 2018-01-04 | 361315001 | 0.910 ppm |
| 2018-02-07 | 365897001 | 0.840 ppm |
| 2018-02-07 | 365897001 | 0.892 ppm |
| 2018-03-01 | 369016001 | 0.830 ppm |
| 2018-03-01 | 369016001 | 0.843 ppm |
| 2018-04-10 | 375382001 | 0.820 ppm |
| 2018-04-10 | 375382001 | 0.848 ppm |
| 2018-05-07 | 380069001 | 0.840 ppm |
| 2018-05-07 | 380069001 | 0.917 ppm |
| 2018-06-12 | 387908001 | 0.840 ppm |
| 2018-06-12 | 387908001 | 0.871 ppm |
| 2018-07-10 | 393135001 | 0.810 ppm |
| 2018-07-10 | 393135001 | 0.897 ppm |
| 2018-08-13 | 400316001 | 0.800 ppm |
| 2018-08-13 | 400316001 | 0.836 ppm |
| 2018-09-12 | 407069001 | 0.820 ppm |
| 2018-09-12 | 407069001 | 0.869 ppm |
| 2018-10-10 | 413607001 | 0.800 ppm |
| 2018-10-10 | 413607001 | 0.900 ppm |
| 2018-11-05 | 417637001 | 0.830 ppm |
| 2018-11-05 | 417637001 | 0.849 ppm |
| 2018-12-05 | 422691001 | 0.800 ppm |
| 2018-12-05 | 422691001 | 0.855 ppm |
| 2019-01-10 | 427263001 | 0.850 ppm |
| 2019-01-10 | 427263001 | 0.891 ppm |
| 2019-02-04 | 429698001 | 0.850 ppm |
| 2019-02-04 | 429698001 | 0.948 ppm |
| 2019-03-14 | 435407001 | 0.860 ppm |
| 2019-03-14 | 435407001 | 0.932 ppm |
| 2019-04-04 | 438801001 | 0.860 ppm |
| 2019-04-04 | 438801001 | 0.911 ppm |
| 2019-05-20 | 446795001 | 0.860 ppm |
| 2019-05-20 | 446795001 | 0.914 ppm |
| 2019-06-12 | 451433001 | 0.820 ppm |
| 2019-06-12 | 451433001 | 0.853 ppm |
| 2019-07-08 | 455684001 | 0.830 ppm |
| 2019-07-08 | 455684001 | 0.845 ppm |
| 2019-08-12 | 462780001 | 0.827 ppm |
| 2019-08-12 | 462780001 | 0.860 ppm |
| 2019-09-16 | 470003001 | 0.774 ppm |
| 2019-09-16 | 470003001 | 0.840 ppm |
| 2019-10-23 | 477865001 | 0.781 ppm |
| 2019-10-23 | 477865001 | 0.800 ppm |
| 2019-11-06 | 480144001 | 0.779 ppm |
| 2019-11-06 | 480144001 | 0.820 ppm |
| 2019-12-09 | 484930001 | 0.829 ppm |
| 2019-12-09 | 484930001 | 0.830 ppm |