Fluoride
Rehoboth Beach Water Department
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.
265
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.467 ppm | 42 | 42 | 0.1000 ppm - 1.13 ppm |
| 2015 | 0.299 ppm | 41 | 38 | ND - 0.580 ppm |
| 2016 | 0.253 ppm | 40 | 37 | ND - 0.560 ppm |
| 2017 | 0.165 ppm | 52 | 29 | ND - 0.560 ppm |
| 2018 | 0.368 ppm | 48 | 40 | ND - 1.14 ppm |
| 2019 | 0.419 ppm | 42 | 35 | ND - 1.17 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 |
|---|---|---|
| 2014-01-14 | S457803 | 0.300 ppm |
| 2014-01-14 | S457804 | 0.240 ppm |
| 2014-01-14 | S457805 | 0.190 ppm |
| 2014-02-11 | S457813 | 0.540 ppm |
| 2014-02-11 | S457814 | 0.350 ppm |
| 2014-02-11 | S505443 | 0.700 ppm |
| 2014-03-11 | S505437 | 0.660 ppm |
| 2014-03-11 | S505438 | 0.490 ppm |
| 2014-03-11 | S505439 | 0.370 ppm |
| 2014-04-08 | S505446 | 0.710 ppm |
| 2014-04-08 | S505447 | 0.520 ppm |
| 2014-04-08 | S505448 | 1.13 ppm |
| 2014-05-20 | S505484 | 0.620 ppm |
| 2014-05-20 | S505485 | 0.640 ppm |
| 2014-05-20 | S505486 | 0.380 ppm |
| 2014-06-10 | S505526 | 0.610 ppm |
| 2014-06-10 | S505528 | 0.1000 ppm |
| 2014-06-10 | S505529 | 0.260 ppm |
| 2014-07-15 | S505556 | 0.560 ppm |
| 2014-07-15 | S505557 | 0.620 ppm |
| 2014-07-15 | S505558 | 0.520 ppm |
| 2014-08-12 | S505722 | 0.620 ppm |
| 2014-08-12 | S505723 | 0.520 ppm |
| 2014-08-12 | S505724 | 0.570 ppm |
| 2014-09-09 | S505841 | 0.610 ppm |
| 2014-09-09 | S505842 | 0.470 ppm |
| 2014-09-09 | S505843 | 0.480 ppm |
| 2014-10-21 | S505886 | 0.380 ppm |
| 2014-10-21 | S505887 | 0.550 ppm |
| 2014-10-21 | S505888 | 0.460 ppm |
| 2014-11-25 | S505889 | 0.310 ppm |
| 2014-11-25 | S580056 | 0.250 ppm |
| 2014-11-25 | S580057 | 0.490 ppm |
| 2014-11-25 | S580060 | 0.380 ppm |
| 2014-12-10 | S588967 | 0.450 ppm |
| 2014-12-10 | S588968 | 0.400 ppm |
| 2014-12-10 | S588969 | 0.410 ppm |
| 2014-12-10 | S588976 | 0.310 ppm |
| 2014-12-23 | S580065 | 0.490 ppm |
| 2014-12-23 | S580066 | 0.350 ppm |
| 2014-12-23 | S580067 | 0.220 ppm |
| 2014-12-23 | S580074 | 0.400 ppm |
| 2015-01-27 | S580079 | 0.430 ppm |
| 2015-01-27 | S580081 | 0.410 ppm |
| 2015-01-27 | S580082 | 0.220 ppm |
| 2015-02-24 | S580095 | 0.400 ppm |
| 2015-02-24 | S580096 | 0.420 ppm |
| 2015-02-24 | S580097 | 0.250 ppm |
| 2015-03-24 | S580107 | 0.320 ppm |
| 2015-03-24 | S580108 | 0.380 ppm |
| 2015-03-24 | S580109 | 0.290 ppm |
| 2015-04-28 | S580122 | 0.500 ppm |
| 2015-04-28 | S580123 | 0.280 ppm |
| 2015-04-28 | S580124 | 0.220 ppm |
| 2015-05-26 | S580441 | 0.480 ppm |
| 2015-05-26 | S580442 | 0.220 ppm |
| 2015-05-26 | S580443 | 0.150 ppm |
| 2015-06-23 | S631702 | 0.580 ppm |
| 2015-06-23 | S631703 | ND |
| 2015-06-23 | S631704 | 0.200 ppm |
| 2015-07-21 | S631721 | 0.390 ppm |
| 2015-07-21 | S631722 | 0.380 ppm |
| 2015-07-21 | S631723 | 0.300 ppm |
| 2015-08-18 | S631778 | 0.370 ppm |
| 2015-08-18 | S631779 | 0.560 ppm |
| 2015-08-18 | S631780 | ND |
| 2015-08-18 | S631781 | 0.370 ppm |
| 2015-09-15 | S631823 | 0.350 ppm |
| 2015-09-15 | S631824 | 0.260 ppm |
| 2015-09-15 | S631825 | 0.250 ppm |
| 2015-09-15 | S631826 | 0.240 ppm |
| 2015-10-27 | S631882 | 0.120 ppm |
| 2015-10-27 | S631883 | 0.230 ppm |
| 2015-10-27 | S631884 | 0.230 ppm |
| 2015-10-27 | S631885 | 0.490 ppm |
| 2015-11-10 | S631892 | 0.520 ppm |
| 2015-11-10 | S631893 | ND |
| 2015-11-10 | S631894 | 0.280 ppm |
| 2015-11-10 | S631895 | 0.250 ppm |
| 2015-12-22 | S631919 | 0.300 ppm |
| 2015-12-22 | S631922 | 0.230 ppm |
| 2015-12-22 | S631923 | 0.240 ppm |
| 2015-12-22 | S631924 | 0.150 ppm |
| 2016-01-26 | S631930 | 0.280 ppm |
| 2016-01-26 | S631931 | 0.490 ppm |
| 2016-01-26 | S631932 | 0.250 ppm |
| 2016-01-26 | S631933 | 0.270 ppm |
| 2016-02-23 | S631945 | 0.160 ppm |
| 2016-02-23 | S631947 | 0.230 ppm |
| 2016-02-23 | S631950 | 0.290 ppm |
| 2016-03-08 | S631957 | 0.240 ppm |
| 2016-03-08 | S631959 | 0.260 ppm |
| 2016-03-22 | S631960 | 0.220 ppm |
| 2016-04-12 | S631969 | 0.340 ppm |
| 2016-04-12 | S631970 | 0.210 ppm |
| 2016-04-12 | S631971 | 0.200 ppm |
| 2016-05-17 | S631998 | 0.250 ppm |
| 2016-05-17 | S631999 | 0.310 ppm |
| 2016-05-17 | S632000 | 0.210 ppm |
| 2016-05-17 | S632001 | 0.210 ppm |
| 2016-06-21 | S696605 | 0.110 ppm |
| 2016-06-21 | S696606 | 0.130 ppm |
| 2016-06-21 | S696607 | 0.240 ppm |
| 2016-06-21 | S696608 | 0.260 ppm |
| 2016-07-19 | S696609 | ND |
| 2016-07-19 | S696610 | 0.1000 ppm |
| 2016-07-19 | S696611 | 0.280 ppm |
| 2016-07-19 | S696612 | 0.510 ppm |
| 2016-08-16 | S696676 | 0.390 ppm |
| 2016-08-16 | S696677 | 0.560 ppm |
| 2016-08-16 | S696678 | 0.210 ppm |
| 2016-08-16 | S696679 | 0.260 ppm |
| 2016-09-20 | S696711 | 0.480 ppm |
| 2016-09-20 | S696712 | 0.190 ppm |
| 2016-09-20 | S696713 | 0.140 ppm |
| 2016-10-18 | S696746 | 0.360 ppm |
| 2016-10-18 | S696748 | 0.180 ppm |
| 2016-11-22 | S696753 | ND |
| 2016-11-22 | S696754 | 0.360 ppm |
| 2016-11-22 | S696755 | 0.380 ppm |
| 2016-12-13 | S696760 | ND |
| 2016-12-13 | S696761 | 0.210 ppm |
| 2016-12-13 | S696762 | 0.340 ppm |
| 2017-01-24 | S665273 | 0.400 ppm |
| 2017-01-24 | S665274 | 0.200 ppm |
| 2017-02-17 | S665286 | 0.410 ppm |
| 2017-02-17 | S665287 | ND |
| 2017-02-17 | S665288 | ND |
| 2017-02-17 | S665289 | 0.270 ppm |
| 2017-03-28 | S665296 | 0.170 ppm |
| 2017-03-28 | S665297 | ND |
| 2017-03-28 | S665298 | 0.420 ppm |
| 2017-03-28 | S665303 | 0.180 ppm |
| 2017-04-18 | S665317 | 0.370 ppm |
| 2017-04-25 | S665322 | 0.420 ppm |
| 2017-04-25 | S665323 | ND |
| 2017-04-25 | S665324 | 0.110 ppm |
| 2017-04-25 | S665325 | 0.240 ppm |
| 2017-05-16 | S665343 | 0.440 ppm |
| 2017-05-16 | S665344 | ND |
| 2017-05-16 | S665345 | ND |
| 2017-05-16 | S665346 | 0.150 ppm |
| 2017-06-20 | S665371 | ND |
| 2017-06-20 | S665372 | ND |
| 2017-06-20 | S665373 | 0.140 ppm |
| 2017-06-20 | S665374 | 0.330 ppm |
| 2017-07-18 | S732220 | 0.490 ppm |
| 2017-07-18 | S732221 | 0.560 ppm |
| 2017-07-18 | S732222 | 0.120 ppm |
| 2017-07-18 | S732223 | 0.360 ppm |
| 2017-08-15 | S732278 | 0.430 ppm |
| 2017-08-15 | S732279 | 0.280 ppm |
| 2017-08-15 | S732280 | 0.1000 ppm |
| 2017-08-15 | S732281 | 0.260 ppm |
| 2017-09-19 | S740855 | 0.360 ppm |
| 2017-09-19 | S740856 | ND |
| 2017-09-19 | S740857 | ND |
| 2017-09-19 | S740858 | ND |
| 2017-09-26 | S740867 | ND |
| 2017-09-26 | S740868 | ND |
| 2017-10-24 | S750591 | ND |
| 2017-10-24 | S750592 | ND |
| 2017-10-24 | S750593 | 0.150 ppm |
| 2017-11-14 | S750424 | 0.290 ppm |
| 2017-11-14 | S750425 | ND |
| 2017-11-14 | S750426 | ND |
| 2017-11-14 | S750427 | ND |
| 2017-11-28 | S750608 | 0.380 ppm |
| 2017-11-28 | S750609 | ND |
| 2017-11-28 | S750610 | 0.210 ppm |
| 2017-11-28 | S750611 | ND |
| 2017-12-12 | S750602 | 0.360 ppm |
| 2017-12-12 | S750603 | ND |
| 2017-12-12 | S750612 | ND |
| 2017-12-12 | S750613 | ND |
| 2018-01-23 | S750623 | 0.160 ppm |
| 2018-01-23 | S750624 | 0.110 ppm |
| 2018-01-23 | S750625 | 0.200 ppm |
| 2018-01-23 | S750626 | ND |
| 2018-02-13 | S750618 | 0.370 ppm |
| 2018-02-13 | S750631 | ND |
| 2018-02-13 | S750632 | ND |
| 2018-02-13 | S750633 | 0.310 ppm |
| 2018-03-27 | S750650 | 0.400 ppm |
| 2018-03-27 | S750652 | 0.200 ppm |
| 2018-03-27 | S780651 | 0.200 ppm |
| 2018-04-24 | S750662 | 0.327 ppm |
| 2018-04-24 | S750663 | 0.438 ppm |
| 2018-04-24 | S750664 | 0.183 ppm |
| 2018-04-24 | S750665 | 0.186 ppm |
| 2018-05-22 | S750702 | 0.0838 ppm |
| 2018-05-22 | S750703 | 0.131 ppm |
| 2018-05-22 | S750704 | 0.306 ppm |
| 2018-05-22 | S750705 | 0.312 ppm |
| 2018-06-26 | S750732 | 0.661 ppm |
| 2018-06-26 | S750733 | 0.489 ppm |
| 2018-06-26 | S750735 | 0.421 ppm |
| 2018-07-24 | S750754 | 0.573 ppm |
| 2018-07-24 | S750755 | 0.498 ppm |
| 2018-07-24 | S750756 | ND |
| 2018-07-24 | S750757 | 0.512 ppm |
| 2018-08-14 | S750773 | 0.502 ppm |
| 2018-08-14 | S750774 | 0.521 ppm |
| 2018-08-14 | S750775 | 0.642 ppm |
| 2018-08-14 | S750776 | 0.381 ppm |
| 2018-09-11 | S804467 | 0.919 ppm |
| 2018-09-11 | S804468 | 0.0531 ppm |
| 2018-09-11 | S804469 | 0.590 ppm |
| 2018-09-11 | S804470 | 0.728 ppm |
| 2018-10-23 | S804527 | 0.367 ppm |
| 2018-10-23 | S804528 | 0.357 ppm |
| 2018-10-23 | S804529 | 0.435 ppm |
| 2018-11-13 | S804534 | 0.598 ppm |
| 2018-11-13 | S804535 | 0.761 ppm |
| 2018-11-13 | S804536 | 0.663 ppm |
| 2018-11-29 | S850887 | ND |
| 2018-11-29 | S850888 | ND |
| 2018-11-29 | S850889 | ND |
| 2018-11-29 | S850890 | ND |
| 2018-12-12 | S804548 | 0.254 ppm |
| 2018-12-12 | S804549 | 0.591 ppm |
| 2018-12-12 | S804550 | 1.14 ppm |
| 2018-12-12 | S804551 | 1.09 ppm |
| 2019-01-08 | S804542 | 0.565 ppm |
| 2019-01-08 | S804543 | 0.822 ppm |
| 2019-01-08 | S804544 | 0.618 ppm |
| 2019-01-08 | S804545 | 0.207 ppm |
| 2019-01-22 | S804563 | ND |
| 2019-01-22 | S804565 | 0.812 ppm |
| 2019-01-22 | S804566 | 0.650 ppm |
| 2019-02-26 | S804573 | 0.607 ppm |
| 2019-02-26 | S804574 | 0.597 ppm |
| 2019-02-26 | S804575 | 0.201 ppm |
| 2019-02-26 | S804576 | 0.611 ppm |
| 2019-03-26 | S804307 | 0.536 ppm |
| 2019-03-26 | S804590 | 0.773 ppm |
| 2019-03-26 | S804591 | 0.774 ppm |
| 2019-04-23 | S804327 | 0.546 ppm |
| 2019-04-23 | S804328 | 0.504 ppm |
| 2019-04-23 | S804329 | 0.594 ppm |
| 2019-05-21 | S804354 | 0.544 ppm |
| 2019-05-21 | S804355 | 0.225 ppm |
| 2019-05-21 | S804356 | ND |
| 2019-06-18 | S804364 | 0.119 ppm |
| 2019-06-18 | S804381 | ND |
| 2019-06-18 | S804382 | 0.183 ppm |
| 2019-07-16 | S804392 | 0.0867 ppm |
| 2019-07-16 | S804393 | 0.389 ppm |
| 2019-07-16 | S804394 | 0.156 ppm |
| 2019-08-20 | S804155 | 0.571 ppm |
| 2019-08-20 | S804156 | 0.217 ppm |
| 2019-08-20 | S804157 | ND |
| 2019-09-24 | S804193 | 0.474 ppm |
| 2019-09-24 | S804194 | 0.258 ppm |
| 2019-09-24 | S804195 | ND |
| 2019-10-01 | S909990 | 0.264 ppm |
| 2019-10-01 | S909993 | ND |
| 2019-10-01 | S909996 | 0.489 ppm |
| 2019-10-29 | S925227 | ND |
| 2019-10-29 | S925246 | 0.572 ppm |
| 2019-11-18 | S925216 | 0.698 ppm |
| 2019-11-26 | S909896 | 0.344 ppm |
| 2019-11-26 | S909898 | 0.949 ppm |
| 2019-12-17 | S909904 | 0.458 ppm |
| 2019-12-17 | S909905 | 1.17 ppm |