Mercury violations in Maryland
5 active public water systems in Maryland had a Mercury violation in the past three years. What Mercury is and why it matters.
Health effects: Chronic exposure to inorganic mercury in water primarily damages the kidneys. Neurological effects — tremors, memory loss, cognitive impairment — are more associated with organic mercury (methylmercury) than with the inorganic form regulated in drinking water. Developing fetuses and young children are most vulnerable.
Systems with a Mercury violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
ST Johns Lutheran Church and School Baltimore County |
140 | 4 | 0 | |
|
Barrelville Allegany County |
130 | 7 | 2 | |
|
Powrmatic Inc. Carroll County |
35 | 4 | 1 | |
|
Our House Job Training Center for Youth Montgomery County |
30 | 5 | 1 | |
|
Calvert Gateway & McDonalds # 16243 Calvert County |
25 | 3 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Mercury, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Mercury alone.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Maryland records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.