TTHM (Total Trihalomethanes) violations in New Hampshire
42 active public water systems in New Hampshire had a TTHM (Total Trihalomethanes) violation in the past three years, 10 of them still unresolved. What TTHM (Total Trihalomethanes) is and why it matters.
Systems with a TTHM (Total Trihalomethanes) violation
Unresolved first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Hudson Water Dept Hudson · Hillsborough County |
16,700 | 1 | 0 | |
|
Claremont Water Dept Claremont · Sullivan County |
9,000 | 2 | 0 | |
|
Wilton Water Works Wilton · Hillsborough County |
1,790 | 2 | 2 | |
|
Contoocook Village Pct Hopkinton · Merrimack County |
1,600 | 3 | 0 | |
|
Canaan Water Dept Canaan · Grafton County |
684 | 5 | 3 | |
|
Andover Village Dist Andover · Merrimack County |
650 | 6 | 4 | |
|
Greenville Est Village Dist Greenville · Hillsborough County |
472 | 3 | 0 | |
|
Rindge Memorial Sch Rindge · Cheshire County |
450 | 4 | 3 | |
|
W Stewartstown Water Pct Stewartstown · Coos County |
428 | 2 | 2 | |
|
Middleton Elementary School Middleton · Strafford County |
174 | 2 | 0 | |
|
Aquarion Water/nh Hampton · Rockingham County |
34,000 | 1 | 0 | |
|
Salem Water Dept Salem · Rockingham County |
21,080 | 1 | 0 | |
|
Exeter Water Dept Exeter · Rockingham County |
12,236 | 2 | 1 | |
|
Peterborough Water Works Peterborough · Hillsborough County |
4,500 | 1 | 0 | |
|
Goffstown Village Pct Goffstown · Hillsborough County |
3,250 | 3 | 0 | |
|
Charlestown Water Works Charlestown · Sullivan County |
2,850 | 1 | 0 | |
|
Bethlehem Village Dist Bethlehem · Grafton County |
1,750 | 2 | 1 | |
|
Epping Water and Sewer Dept Epping · Rockingham County |
1,600 | 2 | 0 | |
|
Emerald Lake Hillsborough · Hillsborough County |
1,300 | 3 | 2 | |
|
Waterville Estate Vlg Dist/w Campton · Grafton County |
1,250 | 2 | 0 | |
|
Lisbon Water Dept Lisbon · Grafton County |
1,010 | 3 | 0 | |
|
NO Haverhill Water and Light Haverhill · Grafton County |
750 | 2 | 0 | |
|
N Walpole Village District/low Walpole · Cheshire County |
625 | 5 | 1 | |
|
New Hampton Village Pct New Hampton · Belknap County |
600 | 4 | 1 | |
|
W and E Windham · Rockingham County |
528 | 1 | 0 | |
|
Cardigan Mountain Sch Canaan · Grafton County |
300 | 2 | 0 | |
|
Crotched Mountain School Greenfield · Hillsborough County |
300 | 7 | 1 | |
|
Granite State Industrial Ctr Bow · Merrimack County |
240 | 2 | 0 | |
|
Sun Valley Hampton · Rockingham County |
200 | 1 | 0 | |
|
Thornhill Condos Stratham · Rockingham County |
175 | 1 | 0 | |
|
Wentworth Cove Estates Laconia · Belknap County |
140 | 2 | 0 | |
|
N Walpole Village Dist/high Walpole · Cheshire County |
125 | 5 | 1 | |
|
Marlborough Estates Marlborough · Cheshire County |
100 | 1 | 0 | |
|
Towne Square Prof Condos Londonderry · Rockingham County |
75 | 2 | 0 | |
|
Upper CT Valley Hospital Colebrook · Coos County |
75 | 2 | 0 | |
|
Acorn Sch Stratham · Rockingham County |
60 | 2 | 1 | |
|
Steele Hill Resort Sanbornton · Belknap County |
60 | 4 | 0 | |
|
Stonearch Condo Assn/kirkwall Stratham · Rockingham County |
52 | 1 | 0 | |
|
Greenfield Commons Greenfield · Hillsborough County |
48 | 2 | 0 | |
|
Camelot Court Nottingham · Rockingham County |
45 | 1 | 0 | |
|
The Square on Amherst Amherst · Hillsborough County |
45 | 2 | 0 | |
|
French Pond Estates Haverhill · Grafton County |
27 | 1 | 0 |
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 New Hampshire 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. Retrieved from ECHO on Oct 11, 2026.