EWG's Tap Water Database — 2019 UPDATE



Town of Princess Anne

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 exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20120.306 ppm12120.240 ppm - 0.580 ppm
20130.313 ppm10100.240 ppm - 0.400 ppm
20140.528 ppm10100.133 ppm - 3.53 ppm
20150.300 ppm98ND - 1.41 ppm
20160.312 ppm13130.230 ppm - 0.400 ppm
20170.307 ppm550.279 ppm - 0.350 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
2012-01-12120112_08_A120100.250 ppm
2012-02-08120208_08_0042440.250 ppm
2012-02-08120208_07_0042440.320 ppm
2012-04-30120430_02_A120500.250 ppm
2012-04-30120430_04_E120500.280 ppm
2012-04-30120430_05_B120500.260 ppm
2012-04-30120430_06_H120500.310 ppm
2012-04-30120430_01_C120500.320 ppm
2012-04-30120430_07_G120500.300 ppm
2012-04-30120430_03_D120500.310 ppm
2012-04-30120430_08_F120500.240 ppm
2012-07-12120712_03_4244050.580 ppm
2013-03-14130314_01_L452800.310 ppm
2013-03-14130314_08_L452800.240 ppm
2013-03-14130314_03_L452800.370 ppm
2013-03-14130314_07_L452800.240 ppm
2013-03-14130314_04_L458050.330 ppm
2013-04-09130409_06_L455800.330 ppm
2013-04-09130409_05_L455800.270 ppm
2013-04-09130409_02_L455800.260 ppm
2013-05-21130521_03_L460550.375 ppm
2013-10-17131017_03_0020450.400 ppm
2014-09-14140914_01_L525120.207 ppm
2014-09-17140917_08_L525120.133 ppm
2014-09-17140917_07_L525120.171 ppm
2014-09-17140917_06_L525120.216 ppm
2014-09-17140917_05_L525120.149 ppm
2014-09-17140917_04_L525120.215 ppm
2014-09-17140917_03_L525120.253 ppm
2014-09-17140917_03_L525120.265 ppm
2014-09-17140917_03_L525123.53 ppm
2014-09-17140917_02_L525120.136 ppm
2015-09-290190002_092915_W0.180 ppm
2015-09-29L5834178-50.170 ppm
2015-12-18PAHKW12280.170 ppm
2015-12-28L5979291_1_A0.218 ppm
2015-12-28L597294_10.160 ppm
2015-12-28PARRNF12280.180 ppm
2015-12-30L5984858_81.41 ppm
2015-12-30L5984858_30.210 ppm
2016-03-03E160036320010.280 ppm
2016-03-30E160036320020.400 ppm
2016-06-22L6332602_40.340 ppm
2016-08-05E170005000020.270 ppm
2016-08-05E170005000010.350 ppm
2016-12-21L6605660_40.320 ppm
2016-12-21L6605660_30.270 ppm
2016-12-21L6605660_20.380 ppm
2016-12-21L6605660_10.260 ppm
2016-12-24L6609497_10.310 ppm
2016-12-27L6607241_30.360 ppm
2016-12-29L6609503_20.280 ppm
2016-12-29L6609503_30.230 ppm
2017-04-04L6753780_20.279 ppm
2017-04-12L6763074_10.350 ppm
2017-04-19L6769607_10.306 ppm
2017-04-19L6769607_50.312 ppm
2017-04-19L6769607_30.288 ppm