Fluoride
Prairie Du Sac 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 | 0.732 ppm | 26 | 24 | ND - 0.980 ppm |
| 2015 | 0.543 ppm | 24 | 24 | 0.118 ppm - 0.741 ppm |
| 2016 | 0.663 ppm | 24 | 24 | 0.580 ppm - 0.768 ppm |
| 2017 | 0.684 ppm | 26 | 26 | 0.220 ppm - 0.789 ppm |
| 2018 | 0.668 ppm | 24 | 24 | 0.600 ppm - 0.700 ppm |
| 2019 | 0.627 ppm | 24 | 24 | 0.560 ppm - 0.670 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 | 114843001 | 0.812 ppm |
| 2014-01-06 | 114843001 | 0.980 ppm |
| 2014-02-19 | 120425001 | 0.750 ppm |
| 2014-02-19 | 120425001 | 0.775 ppm |
| 2014-03-03 | 121499001 | 0.792 ppm |
| 2014-03-03 | 121499001 | 0.900 ppm |
| 2014-04-07 | 126578001 | 0.768 ppm |
| 2014-04-07 | 126578001 | 0.860 ppm |
| 2014-05-05 | 130413001 | 0.760 ppm |
| 2014-05-05 | 130413001 | 0.773 ppm |
| 2014-06-02 | 136200001 | 0.787 ppm |
| 2014-06-02 | 136200001 | 0.820 ppm |
| 2014-07-07 | 143570001 | 0.768 ppm |
| 2014-07-07 | 143570001 | 0.860 ppm |
| 2014-08-04 | 149152001 | 0.840 ppm |
| 2014-08-04 | 149152001 | 0.905 ppm |
| 2014-08-18 | 489583 | ND |
| 2014-08-18 | 489582 | ND |
| 2014-09-02 | 154661001 | 0.780 ppm |
| 2014-09-02 | 154661001 | 0.780 ppm |
| 2014-10-06 | 161958001 | 0.690 ppm |
| 2014-10-06 | 161958001 | 0.783 ppm |
| 2014-11-03 | 167153001 | 0.698 ppm |
| 2014-11-03 | 167153001 | 0.750 ppm |
| 2014-12-01 | 170303001 | 0.650 ppm |
| 2014-12-01 | 170303001 | 0.744 ppm |
| 2015-01-05 | 174301001 | 0.493 ppm |
| 2015-01-05 | 174301001 | 0.550 ppm |
| 2015-02-09 | 178964001 | 0.355 ppm |
| 2015-02-09 | 178964001 | 0.400 ppm |
| 2015-03-02 | 181427001 | 0.127 ppm |
| 2015-03-02 | 181427001 | 0.180 ppm |
| 2015-04-06 | 186398001 | 0.118 ppm |
| 2015-04-06 | 186398001 | 0.140 ppm |
| 2015-05-04 | 191015001 | 0.598 ppm |
| 2015-05-04 | 191015001 | 0.600 ppm |
| 2015-06-01 | 197028001 | 0.680 ppm |
| 2015-06-01 | 197028001 | 0.719 ppm |
| 2015-07-06 | 203736001 | 0.710 ppm |
| 2015-07-06 | 203736001 | 0.741 ppm |
| 2015-08-10 | 210864001 | 0.660 ppm |
| 2015-08-10 | 210864001 | 0.678 ppm |
| 2015-09-08 | 216016001 | 0.640 ppm |
| 2015-09-08 | 216016001 | 0.664 ppm |
| 2015-10-05 | 221948001 | 0.660 ppm |
| 2015-10-05 | 221948001 | 0.675 ppm |
| 2015-11-02 | 226761001 | 0.620 ppm |
| 2015-11-02 | 226761001 | 0.709 ppm |
| 2015-12-07 | 231611001 | 0.650 ppm |
| 2015-12-07 | 231611001 | 0.657 ppm |
| 2016-01-04 | 234359001 | 0.610 ppm |
| 2016-01-04 | 234359001 | 0.649 ppm |
| 2016-02-01 | 238072001 | 0.600 ppm |
| 2016-02-01 | 238072001 | 0.650 ppm |
| 2016-03-14 | 244009001 | 0.580 ppm |
| 2016-03-14 | 244009001 | 0.659 ppm |
| 2016-04-04 | 246896001 | 0.630 ppm |
| 2016-04-04 | 246896001 | 0.650 ppm |
| 2016-05-02 | 251991001 | 0.622 ppm |
| 2016-05-02 | 251991001 | 0.630 ppm |
| 2016-06-06 | 258574001 | 0.670 ppm |
| 2016-06-06 | 258574001 | 0.700 ppm |
| 2016-07-05 | 263868001 | 0.650 ppm |
| 2016-07-05 | 263868001 | 0.689 ppm |
| 2016-08-02 | 269815001 | 0.660 ppm |
| 2016-08-02 | 269815001 | 0.682 ppm |
| 2016-09-06 | 276309001 | 0.650 ppm |
| 2016-09-06 | 276309001 | 0.698 ppm |
| 2016-10-03 | 281876001 | 0.690 ppm |
| 2016-10-03 | 281876001 | 0.698 ppm |
| 2016-11-07 | 288452001 | 0.700 ppm |
| 2016-11-07 | 288452001 | 0.768 ppm |
| 2016-12-05 | 291412001 | 0.670 ppm |
| 2016-12-05 | 291412001 | 0.708 ppm |
| 2017-01-09 | 295639001 | 0.710 ppm |
| 2017-01-09 | 295639001 | 0.756 ppm |
| 2017-02-06 | 298892001 | 0.760 ppm |
| 2017-02-06 | 298892001 | 0.773 ppm |
| 2017-03-06 | 302732001 | 0.730 ppm |
| 2017-03-06 | 302732001 | 0.753 ppm |
| 2017-03-08 | 839324 | 0.220 ppm |
| 2017-03-08 | 839332 | 0.240 ppm |
| 2017-04-03 | 307524001 | 0.720 ppm |
| 2017-04-03 | 307524001 | 0.756 ppm |
| 2017-05-03 | 313817001 | 0.690 ppm |
| 2017-05-03 | 313817001 | 0.713 ppm |
| 2017-06-05 | 319799001 | 0.690 ppm |
| 2017-06-05 | 319799001 | 0.789 ppm |
| 2017-07-10 | 327942001 | 0.680 ppm |
| 2017-07-10 | 327942001 | 0.758 ppm |
| 2017-08-07 | 334030001 | 0.740 ppm |
| 2017-08-07 | 334030001 | 0.758 ppm |
| 2017-09-11 | 341374001 | 0.670 ppm |
| 2017-09-11 | 341374001 | 0.726 ppm |
| 2017-10-16 | 349344001 | 0.680 ppm |
| 2017-10-16 | 349344001 | 0.729 ppm |
| 2017-11-06 | 352814001 | 0.707 ppm |
| 2017-11-06 | 352814001 | 0.710 ppm |
| 2017-12-11 | 358872001 | 0.640 ppm |
| 2017-12-11 | 358872001 | 0.683 ppm |
| 2018-01-08 | 361980001 | 0.691 ppm |
| 2018-01-08 | 361980001 | 0.700 ppm |
| 2018-02-05 | 365631001 | 0.670 ppm |
| 2018-02-05 | 365631001 | 0.672 ppm |
| 2018-03-13 | 371188001 | 0.650 ppm |
| 2018-03-13 | 371188001 | 0.672 ppm |
| 2018-04-09 | 375824001 | 0.650 ppm |
| 2018-04-09 | 375824001 | 0.666 ppm |
| 2018-05-07 | 380519001 | 0.670 ppm |
| 2018-05-07 | 380519001 | 0.679 ppm |
| 2018-06-11 | 388374001 | 0.670 ppm |
| 2018-06-11 | 388374001 | 0.696 ppm |
| 2018-07-09 | 393614001 | 0.620 ppm |
| 2018-07-09 | 393614001 | 0.689 ppm |
| 2018-08-06 | 399155001 | 0.600 ppm |
| 2018-08-06 | 399155001 | 0.670 ppm |
| 2018-09-10 | 406219001 | 0.697 ppm |
| 2018-09-10 | 406219001 | 0.700 ppm |
| 2018-10-09 | 413606001 | 0.660 ppm |
| 2018-10-09 | 413606001 | 0.662 ppm |
| 2018-11-05 | 418117001 | 0.650 ppm |
| 2018-11-05 | 418117001 | 0.683 ppm |
| 2018-12-03 | 422379001 | 0.619 ppm |
| 2018-12-03 | 422379001 | 0.700 ppm |
| 2019-01-07 | 426641001 | 0.630 ppm |
| 2019-01-07 | 426641001 | 0.640 ppm |
| 2019-02-04 | 429975001 | 0.666 ppm |
| 2019-02-04 | 429975001 | 0.670 ppm |
| 2019-03-04 | 433695001 | 0.560 ppm |
| 2019-03-04 | 433695001 | 0.658 ppm |
| 2019-04-08 | 439824001 | 0.576 ppm |
| 2019-04-08 | 439824001 | 0.630 ppm |
| 2019-05-06 | 444382001 | 0.620 ppm |
| 2019-05-06 | 444382001 | 0.632 ppm |
| 2019-06-17 | 452310001 | 0.578 ppm |
| 2019-06-17 | 452310001 | 0.600 ppm |
| 2019-07-08 | 456225001 | 0.619 ppm |
| 2019-07-08 | 456225001 | 0.640 ppm |
| 2019-08-05 | 461707001 | 0.659 ppm |
| 2019-08-05 | 461707001 | 0.670 ppm |
| 2019-09-09 | 468729001 | 0.610 ppm |
| 2019-09-09 | 468729001 | 0.627 ppm |
| 2019-10-15 | 476948001 | 0.569 ppm |
| 2019-10-15 | 476948001 | 0.570 ppm |
| 2019-11-04 | 479586001 | 0.646 ppm |
| 2019-11-04 | 479586001 | 0.660 ppm |
| 2019-12-02 | 483941001 | 0.646 ppm |
| 2019-12-02 | 483941001 | 0.660 ppm |