Fluoride
Genoa City 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 | 0.707 ppm | 26 | 26 | 0.250 ppm - 1.14 ppm |
| 2015 | 0.679 ppm | 24 | 24 | 0.450 ppm - 0.960 ppm |
| 2016 | 0.750 ppm | 24 | 24 | 0.420 ppm - 1.12 ppm |
| 2017 | 0.684 ppm | 26 | 26 | 0.260 ppm - 0.950 ppm |
| 2018 | 0.686 ppm | 24 | 24 | 0.420 ppm - 0.975 ppm |
| 2019 | 0.644 ppm | 24 | 24 | 0.400 ppm - 0.944 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 | 116414001 | 0.735 ppm |
| 2014-01-13 | 116414001 | 0.790 ppm |
| 2014-02-03 | 118917001 | 0.627 ppm |
| 2014-02-03 | 118917001 | 0.710 ppm |
| 2014-03-04 | 122464001 | 0.653 ppm |
| 2014-03-04 | 122464001 | 0.740 ppm |
| 2014-04-01 | 126120001 | 0.634 ppm |
| 2014-04-01 | 126120001 | 0.790 ppm |
| 2014-04-22 | 4040873-01 | 0.250 ppm |
| 2014-04-22 | 4040870-01 | 0.500 ppm |
| 2014-05-06 | 131243001 | 0.616 ppm |
| 2014-05-06 | 131243001 | 0.670 ppm |
| 2014-06-04 | 137797001 | 0.530 ppm |
| 2014-06-04 | 137797001 | 1.14 ppm |
| 2014-07-02 | 144093001 | 0.711 ppm |
| 2014-07-02 | 144093001 | 0.800 ppm |
| 2014-08-04 | 151294001 | 0.706 ppm |
| 2014-08-04 | 151294001 | 0.750 ppm |
| 2014-09-03 | 155146001 | 0.820 ppm |
| 2014-09-03 | 155146001 | 0.837 ppm |
| 2014-10-01 | 161444001 | 0.610 ppm |
| 2014-10-01 | 161444001 | 0.981 ppm |
| 2014-11-03 | 167306001 | 0.620 ppm |
| 2014-11-03 | 167306001 | 0.743 ppm |
| 2014-12-01 | 171154001 | 0.639 ppm |
| 2014-12-01 | 171154001 | 0.780 ppm |
| 2015-01-06 | 174971001 | 0.579 ppm |
| 2015-01-06 | 174971001 | 0.650 ppm |
| 2015-02-03 | 178582001 | 0.560 ppm |
| 2015-02-03 | 178582001 | 0.656 ppm |
| 2015-03-03 | 182215001 | 0.630 ppm |
| 2015-03-03 | 182215001 | 0.671 ppm |
| 2015-04-01 | 185909001 | 0.820 ppm |
| 2015-04-01 | 185909001 | 0.960 ppm |
| 2015-05-04 | 192102001 | 0.588 ppm |
| 2015-05-04 | 192102001 | 0.780 ppm |
| 2015-06-01 | 197710001 | 0.710 ppm |
| 2015-06-01 | 197710001 | 0.948 ppm |
| 2015-07-06 | 204269001 | 0.580 ppm |
| 2015-07-06 | 204269001 | 0.777 ppm |
| 2015-08-04 | 210217001 | 0.450 ppm |
| 2015-08-04 | 210217001 | 0.714 ppm |
| 2015-09-08 | 216706001 | 0.710 ppm |
| 2015-09-08 | 216706001 | 0.720 ppm |
| 2015-10-01 | 222642001 | 0.450 ppm |
| 2015-10-01 | 222642001 | 0.508 ppm |
| 2015-11-02 | 226983001 | 0.659 ppm |
| 2015-11-02 | 226983001 | 0.780 ppm |
| 2015-12-01 | 231038001 | 0.675 ppm |
| 2015-12-01 | 231038001 | 0.710 ppm |
| 2016-01-06 | 236024001 | 0.664 ppm |
| 2016-01-06 | 236024001 | 0.880 ppm |
| 2016-02-03 | 238384001 | 0.420 ppm |
| 2016-02-03 | 238384001 | 0.495 ppm |
| 2016-03-02 | 242185001 | 0.730 ppm |
| 2016-03-02 | 242185001 | 0.837 ppm |
| 2016-04-04 | 247528001 | 0.663 ppm |
| 2016-04-04 | 247528001 | 0.730 ppm |
| 2016-05-03 | 252417001 | 0.560 ppm |
| 2016-05-03 | 252417001 | 0.573 ppm |
| 2016-06-07 | 260364001 | 0.460 ppm |
| 2016-06-07 | 260364001 | 0.589 ppm |
| 2016-07-05 | 265621001 | 0.790 ppm |
| 2016-07-05 | 265621001 | 0.905 ppm |
| 2016-08-01 | 270432001 | 0.720 ppm |
| 2016-08-01 | 270432001 | 0.900 ppm |
| 2016-09-01 | 276492001 | 0.640 ppm |
| 2016-09-01 | 276492001 | 0.669 ppm |
| 2016-10-10 | 283875001 | 0.810 ppm |
| 2016-10-10 | 283875001 | 0.946 ppm |
| 2016-11-07 | 288652001 | 0.957 ppm |
| 2016-11-07 | 288652001 | 0.990 ppm |
| 2016-12-01 | 291859001 | 0.959 ppm |
| 2016-12-01 | 291859001 | 1.12 ppm |
| 2017-01-04 | 295634001 | 0.620 ppm |
| 2017-01-04 | 295634001 | 0.689 ppm |
| 2017-02-06 | 300485001 | 0.691 ppm |
| 2017-02-06 | 300485001 | 0.900 ppm |
| 2017-03-01 | 303308001 | 0.694 ppm |
| 2017-03-01 | 303308001 | 0.810 ppm |
| 2017-04-04 | 309442001 | 0.618 ppm |
| 2017-04-04 | 309442001 | 0.820 ppm |
| 2017-05-04 | 314958001 | 0.617 ppm |
| 2017-05-04 | 314958001 | 0.870 ppm |
| 2017-06-08 | 322058001 | 0.724 ppm |
| 2017-06-08 | 322058001 | 0.950 ppm |
| 2017-07-06 | 327921001 | 0.630 ppm |
| 2017-07-06 | 327921001 | 0.637 ppm |
| 2017-07-25 | 17G0983-01 | 0.260 ppm |
| 2017-07-25 | 17G0984-01 | 0.480 ppm |
| 2017-08-01 | 334016001 | 0.643 ppm |
| 2017-08-01 | 334016001 | 0.650 ppm |
| 2017-09-05 | 340498001 | 0.625 ppm |
| 2017-09-05 | 340498001 | 0.870 ppm |
| 2017-10-03 | 347369001 | 0.639 ppm |
| 2017-10-03 | 347369001 | 0.650 ppm |
| 2017-11-02 | 352819001 | 0.566 ppm |
| 2017-11-02 | 352819001 | 0.800 ppm |
| 2017-12-04 | 358228001 | 0.642 ppm |
| 2017-12-04 | 358228001 | 0.680 ppm |
| 2018-01-03 | 361427001 | 0.420 ppm |
| 2018-01-03 | 361427001 | 0.753 ppm |
| 2018-02-05 | 366128001 | 0.595 ppm |
| 2018-02-05 | 366128001 | 0.720 ppm |
| 2018-03-05 | 370285001 | 0.596 ppm |
| 2018-03-05 | 370285001 | 0.720 ppm |
| 2018-04-02 | 374765001 | 0.604 ppm |
| 2018-04-02 | 374765001 | 0.660 ppm |
| 2018-05-01 | 379832001 | 0.649 ppm |
| 2018-05-01 | 379832001 | 0.680 ppm |
| 2018-06-06 | 387315001 | 0.760 ppm |
| 2018-06-06 | 387315001 | 0.918 ppm |
| 2018-07-03 | 393589001 | 0.630 ppm |
| 2018-07-03 | 393589001 | 0.831 ppm |
| 2018-08-08 | 400216001 | 0.630 ppm |
| 2018-08-08 | 400216001 | 0.656 ppm |
| 2018-09-06 | 406209001 | 0.760 ppm |
| 2018-09-06 | 406209001 | 0.908 ppm |
| 2018-10-04 | 413925001 | 0.660 ppm |
| 2018-10-04 | 413925001 | 0.975 ppm |
| 2018-11-01 | 418579001 | 0.550 ppm |
| 2018-11-01 | 418579001 | 0.584 ppm |
| 2018-12-03 | 424022001 | 0.580 ppm |
| 2018-12-03 | 424022001 | 0.624 ppm |
| 2019-01-02 | 426093001 | 0.591 ppm |
| 2019-01-02 | 426093001 | 0.740 ppm |
| 2019-02-04 | 430615001 | 0.520 ppm |
| 2019-02-04 | 430615001 | 0.634 ppm |
| 2019-03-06 | 435214001 | 0.652 ppm |
| 2019-03-06 | 435214001 | 0.750 ppm |
| 2019-04-02 | 438923001 | 0.610 ppm |
| 2019-04-02 | 438923001 | 0.747 ppm |
| 2019-05-01 | 443643001 | 0.710 ppm |
| 2019-05-01 | 443643001 | 0.715 ppm |
| 2019-06-03 | 450987001 | 0.580 ppm |
| 2019-06-03 | 450987001 | 0.649 ppm |
| 2019-07-01 | 455492001 | 0.830 ppm |
| 2019-07-01 | 455492001 | 0.944 ppm |
| 2019-08-12 | 464020001 | 0.540 ppm |
| 2019-08-12 | 464020001 | 0.667 ppm |
| 2019-09-04 | 468047001 | 0.610 ppm |
| 2019-09-04 | 468047001 | 0.647 ppm |
| 2019-10-01 | 474494001 | 0.638 ppm |
| 2019-10-01 | 474494001 | 0.660 ppm |
| 2019-11-04 | 480476001 | 0.540 ppm |
| 2019-11-04 | 480476001 | 0.621 ppm |
| 2019-12-03 | 484770001 | 0.400 ppm |
| 2019-12-03 | 484770001 | 0.454 ppm |