TTHM (Total Trihalomethanes) violations in Maryland
63 active public water systems in Maryland had a TTHM (Total Trihalomethanes) violation in the past three years, 2 of them in the latest quarter of EPA's data. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
The Neighborhoods at St. Elizabeth Baltimore city County |
162 | 4 | 1 | |
|
N.i.h. Animal Center Montgomery County |
150 | 2 | 0 | |
|
Holland Forest St. Mary's County |
139 | 1 | 0 | |
|
Fox Meadow St. Mary's County |
128 | 1 | 0 | |
|
The Highlands School Harford County |
125 | 2 | 0 | |
|
Tranquility at Fredericktowne Frederick County |
105 | 4 | 1 | |
|
Princess Royale Hotel Distribution Worcester County |
80 | 3 | 0 | |
|
Hearts Desire St. Mary's County |
65 | 1 | 0 | |
|
Mulberry South St. Mary's County |
65 | 1 | 0 | |
|
Wild Goose Crest Subdivision St. Mary's County |
65 | 1 | 0 | |
|
BB Apartments (prev Woc Village Apts) Worcester County |
40 | 5 | 0 | |
|
Belmont Carriage House Conservancy Bldg Howard County |
33 | 2 | 0 | |
|
West Ocean City Business Park Worcester County |
25 | 4 | 2 |
About this data
A system is counted once if any of its violations in the past three years involved TTHM (Total Trihalomethanes), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not TTHM (Total Trihalomethanes) 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.