Fluoride
Grafton 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 | 0.646 ppm | 29 | 29 | 0.120 ppm - 0.790 ppm |
| 2015 | 0.712 ppm | 24 | 24 | 0.580 ppm - 0.800 ppm |
| 2016 | 0.697 ppm | 24 | 24 | 0.616 ppm - 0.770 ppm |
| 2017 | 0.654 ppm | 28 | 28 | 0.220 ppm - 0.770 ppm |
| 2018 | 0.704 ppm | 24 | 24 | 0.645 ppm - 0.810 ppm |
| 2019 | 0.698 ppm | 24 | 24 | 0.628 ppm - 0.810 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 |
|---|---|---|
| 2014-01-07 | 115403001 | 0.694 ppm |
| 2014-01-07 | 115403001 | 0.790 ppm |
| 2014-02-04 | 118776001 | 0.684 ppm |
| 2014-02-04 | 118776001 | 0.720 ppm |
| 2014-03-04 | 122262001 | 0.702 ppm |
| 2014-03-04 | 122262001 | 0.760 ppm |
| 2014-03-10 | 773657 | 0.120 ppm |
| 2014-03-10 | 773672 | 0.190 ppm |
| 2014-03-10 | 773660 | 0.310 ppm |
| 2014-03-10 | 773669 | 0.430 ppm |
| 2014-03-10 | 773675 | 0.600 ppm |
| 2014-04-02 | 126028001 | 0.675 ppm |
| 2014-04-02 | 126028001 | 0.690 ppm |
| 2014-05-08 | 131488001 | 0.699 ppm |
| 2014-05-08 | 131488001 | 0.740 ppm |
| 2014-06-02 | 136171001 | 0.679 ppm |
| 2014-06-02 | 136171001 | 0.720 ppm |
| 2014-07-15 | 145872001 | 0.668 ppm |
| 2014-07-15 | 145872001 | 0.710 ppm |
| 2014-08-01 | 148949001 | 0.742 ppm |
| 2014-08-01 | 148949001 | 0.760 ppm |
| 2014-09-04 | 155140001 | 0.624 ppm |
| 2014-09-04 | 155140001 | 0.720 ppm |
| 2014-10-01 | 161146001 | 0.750 ppm |
| 2014-10-01 | 161146001 | 0.769 ppm |
| 2014-11-02 | 166484001 | 0.640 ppm |
| 2014-11-02 | 166484001 | 0.671 ppm |
| 2014-12-02 | 170660001 | 0.740 ppm |
| 2014-12-02 | 170660001 | 0.750 ppm |
| 2015-01-02 | 174591001 | 0.750 ppm |
| 2015-01-02 | 174591001 | 0.768 ppm |
| 2015-02-02 | 178326001 | 0.707 ppm |
| 2015-02-02 | 178326001 | 0.800 ppm |
| 2015-03-01 | 182303001 | 0.681 ppm |
| 2015-03-01 | 182303001 | 0.720 ppm |
| 2015-04-01 | 185908001 | 0.677 ppm |
| 2015-04-01 | 185908001 | 0.700 ppm |
| 2015-05-01 | 190977001 | 0.704 ppm |
| 2015-05-01 | 190977001 | 0.780 ppm |
| 2015-06-01 | 197040001 | 0.682 ppm |
| 2015-06-01 | 197040001 | 0.700 ppm |
| 2015-07-13 | 205855001 | 0.702 ppm |
| 2015-07-13 | 205855001 | 0.740 ppm |
| 2015-08-04 | 209918001 | 0.703 ppm |
| 2015-08-04 | 209918001 | 0.730 ppm |
| 2015-09-01 | 215589001 | 0.706 ppm |
| 2015-09-01 | 215589001 | 0.750 ppm |
| 2015-10-05 | 222641001 | 0.713 ppm |
| 2015-10-05 | 222641001 | 0.800 ppm |
| 2015-11-11 | 228446001 | 0.580 ppm |
| 2015-11-11 | 228446001 | 0.661 ppm |
| 2015-12-02 | 231105001 | 0.647 ppm |
| 2015-12-02 | 231105001 | 0.680 ppm |
| 2016-01-04 | 234742001 | 0.666 ppm |
| 2016-01-04 | 234742001 | 0.750 ppm |
| 2016-02-02 | 238205001 | 0.675 ppm |
| 2016-02-02 | 238205001 | 0.760 ppm |
| 2016-03-01 | 242312001 | 0.760 ppm |
| 2016-03-01 | 242312001 | 0.770 ppm |
| 2016-04-27 | 251267001 | 0.697 ppm |
| 2016-04-27 | 251267001 | 0.730 ppm |
| 2016-05-03 | 252641001 | 0.672 ppm |
| 2016-05-03 | 252641001 | 0.740 ppm |
| 2016-06-02 | 257784001 | 0.708 ppm |
| 2016-06-02 | 257784001 | 0.720 ppm |
| 2016-07-01 | 264649001 | 0.672 ppm |
| 2016-07-01 | 264649001 | 0.730 ppm |
| 2016-08-01 | 269356001 | 0.654 ppm |
| 2016-08-01 | 269356001 | 0.690 ppm |
| 2016-09-07 | 276339001 | 0.650 ppm |
| 2016-09-07 | 276339001 | 0.652 ppm |
| 2016-10-06 | 282719001 | 0.661 ppm |
| 2016-10-06 | 282719001 | 0.720 ppm |
| 2016-11-02 | 287341001 | 0.655 ppm |
| 2016-11-02 | 287341001 | 0.680 ppm |
| 2016-12-02 | 293111001 | 0.616 ppm |
| 2016-12-02 | 293111001 | 0.710 ppm |
| 2017-01-01 | 295185001 | 0.663 ppm |
| 2017-01-01 | 295185001 | 0.680 ppm |
| 2017-02-02 | 299244001 | 0.636 ppm |
| 2017-02-02 | 299244001 | 0.690 ppm |
| 2017-03-01 | 302231001 | 0.741 ppm |
| 2017-03-01 | 302231001 | 0.770 ppm |
| 2017-03-15 | 978085 | 0.220 ppm |
| 2017-03-15 | 978082 | 0.510 ppm |
| 2017-03-15 | 978088 | 0.760 ppm |
| 2017-03-16 | 978075 | 0.230 ppm |
| 2017-03-16 | 978079 | 0.680 ppm |
| 2017-04-25 | 311944001 | 0.677 ppm |
| 2017-04-25 | 311944001 | 0.750 ppm |
| 2017-05-02 | 313441001 | 0.697 ppm |
| 2017-05-02 | 313441001 | 0.720 ppm |
| 2017-06-02 | 320272001 | 0.637 ppm |
| 2017-06-02 | 320272001 | 0.680 ppm |
| 2017-07-10 | 327901001 | 0.645 ppm |
| 2017-07-10 | 327901001 | 0.700 ppm |
| 2017-08-01 | 334539001 | 0.686 ppm |
| 2017-08-01 | 334539001 | 0.710 ppm |
| 2017-09-06 | 343754001 | 0.670 ppm |
| 2017-09-06 | 343754001 | 0.710 ppm |
| 2017-10-10 | 354201001 | 0.670 ppm |
| 2017-11-09 | 354689001 | 0.682 ppm |
| 2017-11-09 | 354689001 | 0.720 ppm |
| 2017-12-04 | 357891001 | 0.676 ppm |
| 2017-12-04 | 357891001 | 0.710 ppm |
| 2018-01-04 | 361425001 | 0.670 ppm |
| 2018-01-04 | 361425001 | 0.676 ppm |
| 2018-02-19 | 367903001 | 0.728 ppm |
| 2018-02-19 | 367903001 | 0.750 ppm |
| 2018-03-08 | 370242001 | 0.670 ppm |
| 2018-03-08 | 370242001 | 0.685 ppm |
| 2018-04-03 | 374637001 | 0.695 ppm |
| 2018-04-03 | 374637001 | 0.770 ppm |
| 2018-05-08 | 381466001 | 0.741 ppm |
| 2018-05-08 | 381466001 | 0.810 ppm |
| 2018-06-07 | 388370001 | 0.740 ppm |
| 2018-06-07 | 388370001 | 0.751 ppm |
| 2018-07-12 | 395485001 | 0.689 ppm |
| 2018-07-12 | 395485001 | 0.700 ppm |
| 2018-08-23 | 403792001 | 0.660 ppm |
| 2018-08-23 | 403792001 | 0.661 ppm |
| 2018-09-10 | 407287001 | 0.667 ppm |
| 2018-09-10 | 407287001 | 0.670 ppm |
| 2018-10-17 | 415462001 | 0.702 ppm |
| 2018-10-17 | 415462001 | 0.740 ppm |
| 2018-11-15 | 420343001 | 0.693 ppm |
| 2018-11-15 | 420343001 | 0.700 ppm |
| 2018-12-06 | 423063001 | 0.645 ppm |
| 2018-12-06 | 423063001 | 0.690 ppm |
| 2019-01-03 | 426101001 | 0.657 ppm |
| 2019-01-03 | 426101001 | 0.730 ppm |
| 2019-02-03 | 430555001 | 0.637 ppm |
| 2019-02-03 | 430555001 | 0.690 ppm |
| 2019-03-04 | 434863001 | 0.628 ppm |
| 2019-03-04 | 434863001 | 0.660 ppm |
| 2019-04-01 | 438556001 | 0.633 ppm |
| 2019-04-01 | 438556001 | 0.670 ppm |
| 2019-05-07 | 445126001 | 0.707 ppm |
| 2019-05-07 | 445126001 | 0.720 ppm |
| 2019-06-04 | 450098001 | 0.653 ppm |
| 2019-06-04 | 450098001 | 0.690 ppm |
| 2019-07-09 | 457227001 | 0.660 ppm |
| 2019-07-09 | 457227001 | 0.680 ppm |
| 2019-08-01 | 461073001 | 0.751 ppm |
| 2019-08-01 | 461073001 | 0.790 ppm |
| 2019-09-10 | 469931001 | 0.680 ppm |
| 2019-09-10 | 469931001 | 0.686 ppm |
| 2019-10-02 | 474313001 | 0.670 ppm |
| 2019-10-02 | 474313001 | 0.699 ppm |
| 2019-11-04 | 480312001 | 0.782 ppm |
| 2019-11-04 | 480312001 | 0.810 ppm |
| 2019-12-03 | 484769001 | 0.721 ppm |
| 2019-12-03 | 484769001 | 0.750 ppm |