EWG's Tap Water Database — 2019 UPDATE


Mercury (inorganic)

Oak Park Water Service

Mercury is a potent neurotoxin that also damages the kidneys and other internal organs. Mercury enters drinking water from industrial pollution, mining wastes and coal-fired power plants.





Samples exceeding legal limit (MCL)


Samples exceeding
health guidelines

Testing results - average by year

YearAverage resultSamples takenDetectionsRange of results
20120.0467 ppb62ND - 0.190 ppb
20130.01000 ppb72ND - 0.0400 ppb
20140.0175 ppb82ND - 0.120 ppb
20150.00375 ppb81ND - 0.0300 ppb
20160.01000 ppb82ND - 0.0500 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 1.2 ppb

The EWG Health Guideline of 1.2 ppb for mercury (inorganic) was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against harm to internal organs.

EPA Maximum Contaminant
Level (MCL) 2 ppb

The legal limit for inorganic mercury, established in 1991, was based on toxicity studies conducted in laboratory animals in the 1970s and 1980s. This limit does not include any additional consideration of children’s health.

ppb = parts per billion

All test results

Date Lab ID Result