EWG's Tap Water Database — 2021 UPDATE


Perfluorooctane sulfonate (PFOS)

Goldston-Gulf Sanitary District

Perfluorooctane sulfonate (PFOS) is a member of a group of perfluorinated chemicals used in many consumer products. PFOS and other perfluorinated chemicals can cause serious health effects, including cancer, endocrine disruption, accelerated puberty, liver and immune system damage, and thyroid changes. These chemicals are persistent in the environment and they accumulate in people. Click here to read more about perfluorinated chemicals.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20192.50 ppt112.50 ppt

ppt = parts per trillion

State and national drinking water standards and health guidelines

EWG Health Guideline 1 ppt

The EWG Health Guideline of 1 ppt for PFOS was defined by EWG based on studies by Phillipe Grandjean of Harvard University and many other independent researchers who found reduced effectiveness of vaccines and adverse impacts on mammary gland development from exposure to PFOA and PFOS, the two PFAS most widely detected in drinking water. This health guideline applies to the entire class of PFAS detected in water.

EPA Proposed Maximum Contaminant
Level (MCL) 4 ppt

The proposed legal limit for PFOS is 4 ppt, based on studies on people, including children, showing cancer risk.

ppt = parts per trillion

All test results

Date Lab ID Result