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Neurotoxin affecting brain and nervous system. Below are US cities ranked by their measured Mercury levels compared to EPA limits. Higher percentages indicate greater concern.
Vulnerable Populations: Developing fetuses most vulnerable. Mercury crosses placenta and accumulates in fetal brain. Pregnant women should minimize all mercury exposure.
Ranked by percentage of the EPA limit, using one real EPA measurement per water system. Click any city for its full report.
Historical data. Figure shown is the average of the system's 2012–2019 finished-water compliance samples (EPA Six-Year Review 4), non-detects counted as zero. Treat as history, not today's tap water.
EPA's public datasets do not carry per-system results for Mercury in a form we can rank, so no city table is shown.
| Rank | City | State | Level | Period | EPA Limit | % of Limit | Status | Population |
|---|
Most effective for mercury removal.
Effective especially for organic mercury compounds.
Very effective but slow process.
Mercury enters water from industrial discharge, mining, and atmospheric deposition from coal burning. It can also come from natural mineral deposits.
Fish accumulate methylmercury through the food chain, reaching much higher concentrations than water. Both sources should be monitored.
Symptoms include tremors, mood changes, irritability, memory problems, and in severe cases, numbness and vision changes.