Fluoride
Portage 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 | 0.834 ppm | 26 | 26 | 0.660 ppm - 1.05 ppm |
| 2015 | 0.734 ppm | 24 | 24 | 0.540 ppm - 0.880 ppm |
| 2016 | 0.753 ppm | 24 | 24 | 0.607 ppm - 0.910 ppm |
| 2017 | 0.772 ppm | 26 | 26 | 0.580 ppm - 0.960 ppm |
| 2018 | 0.744 ppm | 24 | 24 | 0.610 ppm - 1.03 ppm |
| 2019 | 0.652 ppm | 24 | 24 | 0.369 ppm - 0.870 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 |
|---|---|---|
| 2014-01-06 | 114831001 | 0.873 ppm |
| 2014-01-06 | 114831001 | 1.05 ppm |
| 2014-01-21 | 419875 | 0.810 ppm |
| 2014-01-21 | 419877 | 0.930 ppm |
| 2014-02-03 | 118116001 | 0.802 ppm |
| 2014-02-03 | 118116001 | 0.900 ppm |
| 2014-03-03 | 121334001 | 0.825 ppm |
| 2014-03-03 | 121334001 | 0.850 ppm |
| 2014-04-01 | 125523001 | 0.772 ppm |
| 2014-04-01 | 125523001 | 0.780 ppm |
| 2014-05-05 | 130393001 | 0.803 ppm |
| 2014-05-05 | 130393001 | 0.930 ppm |
| 2014-06-02 | 136091001 | 0.814 ppm |
| 2014-06-02 | 136091001 | 0.870 ppm |
| 2014-07-07 | 143589001 | 0.680 ppm |
| 2014-07-07 | 143589001 | 0.823 ppm |
| 2014-08-04 | 148969001 | 0.660 ppm |
| 2014-08-04 | 148969001 | 0.862 ppm |
| 2014-09-02 | 154451001 | 0.811 ppm |
| 2014-09-02 | 154451001 | 0.890 ppm |
| 2014-10-07 | 162250001 | 0.780 ppm |
| 2014-10-07 | 162250001 | 0.901 ppm |
| 2014-11-03 | 166492001 | 0.824 ppm |
| 2014-11-03 | 166492001 | 0.890 ppm |
| 2014-12-01 | 170300001 | 0.710 ppm |
| 2014-12-01 | 170300001 | 0.849 ppm |
| 2015-01-05 | 174240001 | 0.690 ppm |
| 2015-01-05 | 174240001 | 0.749 ppm |
| 2015-02-02 | 177800001 | 0.783 ppm |
| 2015-02-02 | 177800001 | 0.880 ppm |
| 2015-03-01 | 181420001 | 0.822 ppm |
| 2015-03-01 | 181420001 | 0.880 ppm |
| 2015-04-05 | 186405001 | 0.780 ppm |
| 2015-04-05 | 186405001 | 0.797 ppm |
| 2015-05-11 | 192589001 | 0.720 ppm |
| 2015-05-11 | 192589001 | 0.811 ppm |
| 2015-06-02 | 197087001 | 0.706 ppm |
| 2015-06-02 | 197087001 | 0.710 ppm |
| 2015-07-07 | 204291001 | 0.730 ppm |
| 2015-07-07 | 204291001 | 0.785 ppm |
| 2015-08-03 | 209189001 | 0.600 ppm |
| 2015-08-03 | 209189001 | 0.655 ppm |
| 2015-09-01 | 214949001 | 0.540 ppm |
| 2015-09-01 | 214949001 | 0.698 ppm |
| 2015-10-05 | 221897001 | 0.680 ppm |
| 2015-10-05 | 221897001 | 0.705 ppm |
| 2015-11-02 | 226758001 | 0.560 ppm |
| 2015-11-02 | 226758001 | 0.697 ppm |
| 2015-12-01 | 230746001 | 0.810 ppm |
| 2015-12-01 | 230746001 | 0.824 ppm |
| 2016-01-04 | 234357001 | 0.607 ppm |
| 2016-01-04 | 234357001 | 0.740 ppm |
| 2016-02-01 | 238050001 | 0.729 ppm |
| 2016-02-01 | 238050001 | 0.810 ppm |
| 2016-03-01 | 241867001 | 0.789 ppm |
| 2016-03-01 | 241867001 | 0.910 ppm |
| 2016-04-04 | 246908001 | 0.730 ppm |
| 2016-04-04 | 246908001 | 0.794 ppm |
| 2016-05-02 | 251981001 | 0.760 ppm |
| 2016-05-02 | 251981001 | 0.850 ppm |
| 2016-06-06 | 258565001 | 0.680 ppm |
| 2016-06-06 | 258565001 | 0.771 ppm |
| 2016-07-05 | 263879001 | 0.740 ppm |
| 2016-07-05 | 263879001 | 0.794 ppm |
| 2016-08-01 | 269369001 | 0.660 ppm |
| 2016-08-01 | 269369001 | 0.765 ppm |
| 2016-09-06 | 275980001 | 0.660 ppm |
| 2016-09-06 | 275980001 | 0.754 ppm |
| 2016-10-11 | 283553001 | 0.657 ppm |
| 2016-10-11 | 283553001 | 0.790 ppm |
| 2016-11-01 | 286956001 | 0.790 ppm |
| 2016-11-01 | 286956001 | 0.807 ppm |
| 2016-12-05 | 291384001 | 0.690 ppm |
| 2016-12-05 | 291384001 | 0.783 ppm |
| 2017-01-03 | 824523 | 0.580 ppm |
| 2017-01-03 | 294903001 | 0.650 ppm |
| 2017-01-03 | 824505 | 0.740 ppm |
| 2017-01-03 | 294903001 | 0.801 ppm |
| 2017-02-06 | 298876001 | 0.791 ppm |
| 2017-02-06 | 298876001 | 0.960 ppm |
| 2017-03-06 | 302755001 | 0.748 ppm |
| 2017-03-06 | 302755001 | 0.890 ppm |
| 2017-04-03 | 307568001 | 0.742 ppm |
| 2017-04-03 | 307568001 | 0.820 ppm |
| 2017-05-01 | 313109001 | 0.766 ppm |
| 2017-05-01 | 313109001 | 0.830 ppm |
| 2017-06-05 | 319806001 | 0.720 ppm |
| 2017-06-05 | 319806001 | 0.815 ppm |
| 2017-07-10 | 327324001 | 0.755 ppm |
| 2017-07-10 | 327324001 | 0.880 ppm |
| 2017-08-01 | 332862001 | 0.720 ppm |
| 2017-08-01 | 332862001 | 0.900 ppm |
| 2017-09-05 | 340098001 | 0.660 ppm |
| 2017-09-05 | 340098001 | 0.779 ppm |
| 2017-10-02 | 346425001 | 0.630 ppm |
| 2017-10-02 | 346425001 | 0.785 ppm |
| 2017-11-06 | 352802001 | 0.640 ppm |
| 2017-11-06 | 352802001 | 0.847 ppm |
| 2017-12-04 | 357438001 | 0.793 ppm |
| 2017-12-04 | 357438001 | 0.820 ppm |
| 2018-01-02 | 361125001 | 0.809 ppm |
| 2018-01-02 | 361125001 | 0.810 ppm |
| 2018-02-05 | 365600001 | 0.797 ppm |
| 2018-02-05 | 365600001 | 1.03 ppm |
| 2018-03-05 | 369635001 | 0.710 ppm |
| 2018-03-05 | 369635001 | 0.714 ppm |
| 2018-04-03 | 374459001 | 0.723 ppm |
| 2018-04-03 | 374459001 | 0.770 ppm |
| 2018-05-01 | 379424001 | 0.715 ppm |
| 2018-05-01 | 379424001 | 0.750 ppm |
| 2018-06-04 | 386151001 | 0.610 ppm |
| 2018-06-04 | 386151001 | 0.732 ppm |
| 2018-07-09 | 393054001 | 0.700 ppm |
| 2018-07-09 | 393054001 | 0.763 ppm |
| 2018-08-06 | 399168001 | 0.660 ppm |
| 2018-08-06 | 399168001 | 0.946 ppm |
| 2018-09-04 | 405140001 | 0.650 ppm |
| 2018-09-04 | 405140001 | 0.686 ppm |
| 2018-10-01 | 411853001 | 0.706 ppm |
| 2018-10-01 | 411853001 | 0.860 ppm |
| 2018-11-05 | 418102001 | 0.658 ppm |
| 2018-11-05 | 418102001 | 0.670 ppm |
| 2018-12-03 | 422378001 | 0.662 ppm |
| 2018-12-03 | 422378001 | 0.730 ppm |
| 2019-01-07 | 426622001 | 0.600 ppm |
| 2019-01-07 | 426622001 | 0.614 ppm |
| 2019-02-04 | 430419001 | 0.369 ppm |
| 2019-02-04 | 430419001 | 0.390 ppm |
| 2019-03-04 | 433656001 | 0.520 ppm |
| 2019-03-04 | 433656001 | 0.666 ppm |
| 2019-04-01 | 438153001 | 0.635 ppm |
| 2019-04-01 | 438153001 | 0.740 ppm |
| 2019-05-06 | 444358001 | 0.672 ppm |
| 2019-05-06 | 444358001 | 0.870 ppm |
| 2019-06-03 | 449422001 | 0.670 ppm |
| 2019-06-03 | 449422001 | 0.677 ppm |
| 2019-07-08 | 456217001 | 0.660 ppm |
| 2019-07-08 | 456217001 | 0.668 ppm |
| 2019-08-05 | 461708001 | 0.664 ppm |
| 2019-08-05 | 461708001 | 0.670 ppm |
| 2019-09-03 | 467532001 | 0.670 ppm |
| 2019-09-03 | 467532001 | 0.676 ppm |
| 2019-10-01 | 473944001 | 0.640 ppm |
| 2019-10-01 | 473944001 | 0.703 ppm |
| 2019-11-04 | 479581001 | 0.702 ppm |
| 2019-11-04 | 479581001 | 0.750 ppm |
| 2019-12-02 | 483934001 | 0.673 ppm |
| 2019-12-02 | 483934001 | 0.740 ppm |