EWG's Tap Water Database — 2019 UPDATE



City of Gulfport

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
20120.289 ppm440.200 ppm - 0.385 ppm
20140.242 ppm11110.174 ppm - 0.412 ppm
20150.264 ppm17170.180 ppm - 0.403 ppm
20170.259 ppm550.178 ppm - 0.374 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
2012-04-04120405-019IN0.200 ppm
2012-11-26121127-004IN0.241 ppm
2012-11-26121127-003IN0.328 ppm
2012-11-26121127-002IN0.385 ppm
2014-04-09140410-006IN0.235 ppm
2014-04-09140410-007IN0.231 ppm
2014-04-09140410-008IN0.231 ppm
2014-04-09140410-009IN0.175 ppm
2014-04-09140410-010IN0.177 ppm
2014-04-09140410-018IN0.412 ppm
2014-04-09140410-019IN0.214 ppm
2014-04-09140410-020IN0.174 ppm
2014-04-09140410-021IN0.374 ppm
2014-04-09140410-022IN0.216 ppm
2014-04-09140410-023IN0.225 ppm
2015-03-04150305-025IN0.202 ppm
2015-03-04150305-020IN0.180 ppm
2015-03-04150305-019IN0.262 ppm
2015-03-04150305-018IN0.256 ppm
2015-03-04150305-017IN0.250 ppm
2015-03-04150305-001IN0.205 ppm
2015-03-04150305-002IN0.403 ppm
2015-03-04150305-003IN0.364 ppm
2015-03-04150305-004IN0.380 ppm
2015-03-04150305-005IN0.367 ppm
2015-03-04150305-006IN0.214 ppm
2015-03-04150305-007IN0.220 ppm
2015-03-04150305-016IN0.243 ppm
2015-03-04150305-015IN0.236 ppm
2015-03-04150305-010IN0.272 ppm
2015-03-04150305-009IN0.215 ppm
2015-03-04150305-008IN0.215 ppm
2017-05-10170511-004IN0.374 ppm
2017-05-10170511-003IN0.178 ppm
2017-05-10170511-002IN0.330 ppm
2017-05-10170511-001IN0.197 ppm
2017-05-22170523-004IN0.215 ppm