Fluoride
Eau Claire 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 | 1.04 ppm | 25 | 25 | 0.902 ppm - 1.17 ppm |
| 2015 | 0.840 ppm | 24 | 24 | 0.619 ppm - 1.14 ppm |
| 2016 | 0.615 ppm | 25 | 25 | 0.0640 ppm - 0.750 ppm |
| 2017 | 0.592 ppm | 25 | 25 | 0.437 ppm - 0.700 ppm |
| 2018 | 0.563 ppm | 24 | 24 | 0.491 ppm - 0.680 ppm |
| 2019 | 0.558 ppm | 24 | 24 | 0.513 ppm - 0.600 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 |
|---|---|---|
| 2014-01-23 | 117451001 | 0.971 ppm |
| 2014-01-23 | 117451001 | 0.990 ppm |
| 2014-02-06 | 118890001 | 0.993 ppm |
| 2014-02-06 | 118890001 | 1.09 ppm |
| 2014-03-14 | 123415001 | 1.000 ppm |
| 2014-03-14 | 123415001 | 1.13 ppm |
| 2014-04-22 | 129312001 | 0.918 ppm |
| 2014-04-22 | 129312001 | 1.000 ppm |
| 2014-05-21 | 134701001 | 1.000 ppm |
| 2014-05-21 | 134701001 | 1.000 ppm |
| 2014-06-19 | 140718001 | 0.990 ppm |
| 2014-06-19 | 140718001 | 1.01 ppm |
| 2014-07-18 | 147388001 | 1.06 ppm |
| 2014-07-18 | 147388001 | 1.13 ppm |
| 2014-07-21 | 804375 | 1.000 ppm |
| 2014-08-26 | 154210001 | 0.902 ppm |
| 2014-08-26 | 154210001 | 0.980 ppm |
| 2014-09-25 | 160126001 | 0.960 ppm |
| 2014-09-25 | 160126001 | 1.10 ppm |
| 2014-10-15 | 164287001 | 1.02 ppm |
| 2014-10-15 | 164287001 | 1.15 ppm |
| 2014-11-20 | 169699001 | 1.13 ppm |
| 2014-11-20 | 169699001 | 1.17 ppm |
| 2014-12-12 | 172529001 | 1.11 ppm |
| 2014-12-12 | 172529001 | 1.13 ppm |
| 2015-01-22 | 176919001 | 1.08 ppm |
| 2015-01-22 | 176919001 | 1.13 ppm |
| 2015-02-04 | 178580001 | 1.13 ppm |
| 2015-02-04 | 178580001 | 1.14 ppm |
| 2015-03-18 | 184459001 | 1.11 ppm |
| 2015-03-18 | 184459001 | 1.14 ppm |
| 2015-04-21 | 189718001 | 1.08 ppm |
| 2015-04-21 | 189718001 | 1.10 ppm |
| 2015-05-19 | 195227001 | 0.790 ppm |
| 2015-05-19 | 195227001 | 0.822 ppm |
| 2015-06-09 | 199319001 | 0.640 ppm |
| 2015-06-09 | 199319001 | 0.749 ppm |
| 2015-07-06 | 204599001 | 0.665 ppm |
| 2015-07-06 | 204599001 | 0.700 ppm |
| 2015-08-11 | 211857001 | 0.619 ppm |
| 2015-08-11 | 211857001 | 0.660 ppm |
| 2015-09-03 | 215716001 | 0.690 ppm |
| 2015-09-03 | 215716001 | 0.700 ppm |
| 2015-10-01 | 221376001 | 0.692 ppm |
| 2015-10-01 | 221376001 | 0.730 ppm |
| 2015-11-05 | 227468001 | 0.696 ppm |
| 2015-11-05 | 227468001 | 0.720 ppm |
| 2015-12-01 | 230985001 | 0.681 ppm |
| 2015-12-01 | 230985001 | 0.690 ppm |
| 2016-01-05 | 235063001 | 0.680 ppm |
| 2016-01-05 | 235063001 | 0.750 ppm |
| 2016-02-09 | 239486001 | 0.660 ppm |
| 2016-02-09 | 239486001 | 0.740 ppm |
| 2016-03-08 | 243567001 | 0.649 ppm |
| 2016-03-08 | 243567001 | 0.690 ppm |
| 2016-04-11 | 248797001 | 0.594 ppm |
| 2016-04-11 | 248797001 | 0.660 ppm |
| 2016-05-10 | 253877001 | 0.624 ppm |
| 2016-05-10 | 253877001 | 0.650 ppm |
| 2016-06-03 | 257858001 | 0.598 ppm |
| 2016-06-03 | 257858001 | 0.700 ppm |
| 2016-07-19 | 267831001 | 0.533 ppm |
| 2016-07-19 | 267831001 | 0.650 ppm |
| 2016-08-08 | 271022001 | 0.604 ppm |
| 2016-08-08 | 271022001 | 0.640 ppm |
| 2016-09-14 | 278123001 | 0.584 ppm |
| 2016-09-14 | 278123001 | 0.600 ppm |
| 2016-10-10 | 283865001 | 0.650 ppm |
| 2016-10-10 | 283865001 | 0.659 ppm |
| 2016-11-03 | 957174 | 0.0640 ppm |
| 2016-11-10 | 289413001 | 0.570 ppm |
| 2016-11-10 | 289413001 | 0.627 ppm |
| 2016-12-06 | 295186001 | 0.600 ppm |
| 2016-12-06 | 295186001 | 0.608 ppm |
| 2017-01-09 | 296074001 | 0.585 ppm |
| 2017-01-09 | 296074001 | 0.600 ppm |
| 2017-02-06 | 299275001 | 0.600 ppm |
| 2017-02-06 | 299275001 | 0.630 ppm |
| 2017-02-21 | 974477 | 0.620 ppm |
| 2017-03-08 | 303440001 | 0.590 ppm |
| 2017-03-08 | 303440001 | 0.700 ppm |
| 2017-04-03 | 308271001 | 0.598 ppm |
| 2017-04-03 | 308271001 | 0.600 ppm |
| 2017-05-01 | 313537001 | 0.552 ppm |
| 2017-05-01 | 313537001 | 0.590 ppm |
| 2017-06-02 | 319850001 | 0.580 ppm |
| 2017-06-02 | 319850001 | 0.586 ppm |
| 2017-07-05 | 326345001 | 0.437 ppm |
| 2017-07-05 | 326345001 | 0.570 ppm |
| 2017-08-08 | 334908001 | 0.590 ppm |
| 2017-08-08 | 334908001 | 0.598 ppm |
| 2017-09-13 | 342486001 | 0.550 ppm |
| 2017-09-13 | 342486001 | 0.591 ppm |
| 2017-10-04 | 347340001 | 0.569 ppm |
| 2017-10-04 | 347340001 | 0.590 ppm |
| 2017-11-16 | 355224001 | 0.582 ppm |
| 2017-11-16 | 355224001 | 0.660 ppm |
| 2017-12-11 | 359277001 | 0.594 ppm |
| 2017-12-11 | 359277001 | 0.640 ppm |
| 2018-01-16 | 363513001 | 0.545 ppm |
| 2018-01-16 | 363513001 | 0.620 ppm |
| 2018-02-15 | 367572001 | 0.526 ppm |
| 2018-02-15 | 367572001 | 0.590 ppm |
| 2018-03-21 | 372648001 | 0.517 ppm |
| 2018-03-21 | 372648001 | 0.560 ppm |
| 2018-04-19 | 377318001 | 0.519 ppm |
| 2018-04-19 | 377318001 | 0.600 ppm |
| 2018-05-16 | 383279001 | 0.569 ppm |
| 2018-05-16 | 383279001 | 0.590 ppm |
| 2018-06-20 | 390399001 | 0.491 ppm |
| 2018-06-20 | 390399001 | 0.620 ppm |
| 2018-07-10 | 393771001 | 0.510 ppm |
| 2018-07-10 | 393771001 | 0.581 ppm |
| 2018-08-15 | 401717001 | 0.540 ppm |
| 2018-08-15 | 401717001 | 0.567 ppm |
| 2018-09-19 | 409421001 | 0.530 ppm |
| 2018-09-19 | 409421001 | 0.578 ppm |
| 2018-10-10 | 413987001 | 0.541 ppm |
| 2018-10-10 | 413987001 | 0.550 ppm |
| 2018-11-19 | 420907001 | 0.547 ppm |
| 2018-11-19 | 420907001 | 0.680 ppm |
| 2018-12-10 | 424346001 | 0.555 ppm |
| 2018-12-10 | 424346001 | 0.590 ppm |
| 2019-01-22 | 429125001 | 0.560 ppm |
| 2019-01-22 | 429125001 | 0.576 ppm |
| 2019-02-13 | 431615001 | 0.536 ppm |
| 2019-02-13 | 431615001 | 0.540 ppm |
| 2019-03-12 | 435567001 | 0.525 ppm |
| 2019-03-12 | 435567001 | 0.600 ppm |
| 2019-04-10 | 440219001 | 0.530 ppm |
| 2019-04-10 | 440219001 | 0.600 ppm |
| 2019-05-13 | 446515001 | 0.530 ppm |
| 2019-05-13 | 446515001 | 0.535 ppm |
| 2019-06-17 | 453104001 | 0.550 ppm |
| 2019-06-17 | 453104001 | 0.568 ppm |
| 2019-07-09 | 457253001 | 0.530 ppm |
| 2019-07-09 | 457253001 | 0.552 ppm |
| 2019-08-12 | 463619001 | 0.590 ppm |
| 2019-08-12 | 463619001 | 0.596 ppm |
| 2019-09-09 | 469896001 | 0.570 ppm |
| 2019-09-09 | 469896001 | 0.581 ppm |
| 2019-10-07 | 476952001 | 0.552 ppm |
| 2019-10-07 | 476952001 | 0.560 ppm |
| 2019-11-06 | 480478001 | 0.513 ppm |
| 2019-11-06 | 480478001 | 0.560 ppm |
| 2019-12-10 | 485987001 | 0.535 ppm |
| 2019-12-10 | 485987001 | 0.600 ppm |