Fluoride
South Milwaukee 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 |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | 0.737 ppm | 25 | 25 | 0.640 ppm - 0.890 ppm |
| 2015 | 0.710 ppm | 25 | 25 | 0.600 ppm - 0.860 ppm |
| 2016 | 0.717 ppm | 25 | 25 | 0.650 ppm - 0.820 ppm |
| 2017 | 0.724 ppm | 25 | 25 | 0.656 ppm - 0.820 ppm |
| 2018 | 0.699 ppm | 25 | 25 | 0.590 ppm - 0.880 ppm |
| 2019 | 0.685 ppm | 25 | 25 | 0.540 ppm - 0.790 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 | 116559001 | 0.780 ppm |
| 2014-01-13 | 116559001 | 0.815 ppm |
| 2014-02-04 | 118862001 | 0.690 ppm |
| 2014-02-04 | 118862001 | 0.758 ppm |
| 2014-03-06 | 122252001 | 0.760 ppm |
| 2014-03-06 | 122252001 | 0.890 ppm |
| 2014-04-07 | 126715001 | 0.640 ppm |
| 2014-04-07 | 126715001 | 0.679 ppm |
| 2014-04-07 | 778282 | 0.800 ppm |
| 2014-05-07 | 131512001 | 0.686 ppm |
| 2014-05-07 | 131512001 | 0.730 ppm |
| 2014-06-02 | 137036001 | 0.640 ppm |
| 2014-06-02 | 137036001 | 0.710 ppm |
| 2014-07-20 | 146770001 | 0.720 ppm |
| 2014-07-20 | 146770001 | 0.746 ppm |
| 2014-08-06 | 150175001 | 0.720 ppm |
| 2014-08-06 | 150175001 | 0.736 ppm |
| 2014-09-09 | 156611001 | 0.707 ppm |
| 2014-09-09 | 156611001 | 0.750 ppm |
| 2014-10-06 | 161674001 | 0.741 ppm |
| 2014-10-06 | 161674001 | 0.760 ppm |
| 2014-11-06 | 167582001 | 0.699 ppm |
| 2014-11-06 | 167582001 | 0.800 ppm |
| 2014-12-03 | 171322001 | 0.730 ppm |
| 2014-12-03 | 171322001 | 0.741 ppm |
| 2015-01-09 | 175307001 | 0.698 ppm |
| 2015-01-09 | 175307001 | 0.780 ppm |
| 2015-02-02 | 178927001 | 0.729 ppm |
| 2015-02-02 | 178927001 | 0.860 ppm |
| 2015-03-02 | 181871001 | 0.667 ppm |
| 2015-03-02 | 181871001 | 0.700 ppm |
| 2015-03-03 | 846044 | 0.710 ppm |
| 2015-04-13 | 187626001 | 0.600 ppm |
| 2015-04-13 | 187626001 | 0.678 ppm |
| 2015-05-15 | 194808001 | 0.610 ppm |
| 2015-05-15 | 194808001 | 0.709 ppm |
| 2015-06-01 | 197456001 | 0.690 ppm |
| 2015-06-01 | 197456001 | 0.728 ppm |
| 2015-07-13 | 205854001 | 0.684 ppm |
| 2015-07-13 | 205854001 | 0.790 ppm |
| 2015-08-13 | 211856001 | 0.681 ppm |
| 2015-08-13 | 211856001 | 0.710 ppm |
| 2015-09-09 | 216702001 | 0.735 ppm |
| 2015-09-09 | 216702001 | 0.800 ppm |
| 2015-10-05 | 222010001 | 0.690 ppm |
| 2015-10-05 | 222010001 | 0.711 ppm |
| 2015-11-05 | 227458001 | 0.660 ppm |
| 2015-11-05 | 227458001 | 0.706 ppm |
| 2015-12-02 | 231081001 | 0.690 ppm |
| 2015-12-02 | 231081001 | 0.726 ppm |
| 2016-01-08 | 235294001 | 0.695 ppm |
| 2016-01-08 | 235294001 | 0.820 ppm |
| 2016-02-03 | 238278001 | 0.705 ppm |
| 2016-02-03 | 238278001 | 0.750 ppm |
| 2016-03-03 | 242314001 | 0.690 ppm |
| 2016-03-03 | 242314001 | 0.697 ppm |
| 2016-03-07 | 908300 | 0.710 ppm |
| 2016-04-07 | 247654001 | 0.658 ppm |
| 2016-04-07 | 247654001 | 0.760 ppm |
| 2016-05-04 | 252868001 | 0.703 ppm |
| 2016-05-04 | 252868001 | 0.780 ppm |
| 2016-06-02 | 257778001 | 0.690 ppm |
| 2016-06-02 | 257778001 | 0.712 ppm |
| 2016-07-04 | 263888001 | 0.650 ppm |
| 2016-07-04 | 263888001 | 0.675 ppm |
| 2016-08-09 | 271614001 | 0.687 ppm |
| 2016-08-09 | 271614001 | 0.710 ppm |
| 2016-09-06 | 276297001 | 0.722 ppm |
| 2016-09-06 | 276297001 | 0.750 ppm |
| 2016-10-02 | 282339001 | 0.701 ppm |
| 2016-10-02 | 282339001 | 0.790 ppm |
| 2016-11-04 | 287424001 | 0.693 ppm |
| 2016-11-04 | 287424001 | 0.760 ppm |
| 2016-12-05 | 291915001 | 0.706 ppm |
| 2016-12-05 | 291915001 | 0.720 ppm |
| 2017-01-05 | 295237001 | 0.690 ppm |
| 2017-01-05 | 295237001 | 0.820 ppm |
| 2017-02-03 | 299247001 | 0.702 ppm |
| 2017-02-03 | 299247001 | 0.810 ppm |
| 2017-03-01 | 302112001 | 0.662 ppm |
| 2017-03-01 | 302112001 | 0.730 ppm |
| 2017-04-03 | 307960001 | 0.704 ppm |
| 2017-04-03 | 307960001 | 0.810 ppm |
| 2017-04-19 | 984213 | 0.810 ppm |
| 2017-05-09 | 315236001 | 0.696 ppm |
| 2017-05-09 | 315236001 | 0.790 ppm |
| 2017-06-05 | 320275001 | 0.710 ppm |
| 2017-06-05 | 320275001 | 0.750 ppm |
| 2017-07-10 | 327937001 | 0.656 ppm |
| 2017-07-10 | 327937001 | 0.740 ppm |
| 2017-08-09 | 334964001 | 0.685 ppm |
| 2017-08-09 | 334964001 | 0.700 ppm |
| 2017-09-06 | 340656001 | 0.702 ppm |
| 2017-09-06 | 340656001 | 0.720 ppm |
| 2017-10-05 | 347367001 | 0.659 ppm |
| 2017-10-05 | 347367001 | 0.700 ppm |
| 2017-11-03 | 353279001 | 0.677 ppm |
| 2017-11-03 | 353279001 | 0.680 ppm |
| 2017-12-05 | 358232001 | 0.720 ppm |
| 2017-12-05 | 358232001 | 0.770 ppm |
| 2018-01-11 | 362575001 | 0.703 ppm |
| 2018-01-11 | 362575001 | 0.780 ppm |
| 2018-02-06 | 366120001 | 0.718 ppm |
| 2018-02-06 | 366120001 | 0.720 ppm |
| 2018-03-05 | 369789001 | 0.690 ppm |
| 2018-03-05 | 369789001 | 0.700 ppm |
| 2018-04-03 | 1048124 | 0.690 ppm |
| 2018-04-05 | 374867001 | 0.674 ppm |
| 2018-04-05 | 374867001 | 0.720 ppm |
| 2018-05-01 | 379779001 | 0.630 ppm |
| 2018-05-01 | 379779001 | 0.705 ppm |
| 2018-06-01 | 385576001 | 0.719 ppm |
| 2018-06-01 | 385576001 | 0.810 ppm |
| 2018-07-03 | 392309001 | 0.703 ppm |
| 2018-07-03 | 392309001 | 0.880 ppm |
| 2018-08-02 | 398481001 | 0.640 ppm |
| 2018-08-02 | 398481001 | 0.734 ppm |
| 2018-09-10 | 407285001 | 0.650 ppm |
| 2018-09-10 | 407285001 | 0.704 ppm |
| 2018-10-03 | 412507001 | 0.640 ppm |
| 2018-10-03 | 412507001 | 0.672 ppm |
| 2018-11-01 | 417417001 | 0.640 ppm |
| 2018-11-01 | 417417001 | 0.719 ppm |
| 2018-12-03 | 422385001 | 0.590 ppm |
| 2018-12-03 | 422385001 | 0.641 ppm |
| 2019-01-03 | 426091001 | 0.715 ppm |
| 2019-01-03 | 426091001 | 0.720 ppm |
| 2019-02-04 | 430412001 | 0.679 ppm |
| 2019-02-04 | 430412001 | 0.760 ppm |
| 2019-03-04 | 1107530 | 0.660 ppm |
| 2019-03-04 | 434044001 | 0.674 ppm |
| 2019-03-04 | 434044001 | 0.740 ppm |
| 2019-04-03 | 438826001 | 0.674 ppm |
| 2019-04-03 | 438826001 | 0.760 ppm |
| 2019-05-01 | 446262001 | 0.724 ppm |
| 2019-05-01 | 446262001 | 0.790 ppm |
| 2019-06-03 | 450010001 | 0.701 ppm |
| 2019-06-03 | 450010001 | 0.770 ppm |
| 2019-07-02 | 455494001 | 0.641 ppm |
| 2019-07-02 | 455494001 | 0.780 ppm |
| 2019-08-01 | 460885001 | 0.625 ppm |
| 2019-08-01 | 460885001 | 0.640 ppm |
| 2019-09-05 | 468034001 | 0.540 ppm |
| 2019-09-05 | 468034001 | 0.590 ppm |
| 2019-10-01 | 474300001 | 0.640 ppm |
| 2019-10-01 | 474300001 | 0.678 ppm |
| 2019-11-04 | 479591001 | 0.593 ppm |
| 2019-11-04 | 479591001 | 0.750 ppm |
| 2019-12-02 | 484334001 | 0.612 ppm |
| 2019-12-02 | 484334001 | 0.660 ppm |