Merrimack, NH
Transparent derived index from EPA TRI / SDWIS / Superfund extracts: not an official EPA rating. Fixed caps: facilities ≤25 pts (50+ = max), log10 releases ≤25 pts, Superfund ≤25 pts (5/site), health-violation systems ≤15 pts (3/system), high-chemical facilities ≤10 pts. Bands: High ≥60, Moderate ≥30. See methodology.
Environmental data for Merrimack in New Hampshire · Population: 155,018
TRI sites such as Watts Regulator Co DBA Webster Valve; Merrimack Station; Elektrisola Inc.; SDWIS systems such as CONCORD WATER DEPT; FRANKLIN WATER WORKS; PEMBROKE WATER WORKS anchor Merrimack, NH's EPA extract. Derived burden score 49/100 (Moderate Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.
Health-flagged SDWIS rows in Merrimack include CONTOOCOOK VILLAGE PCT; WARNER VILLAGE WATER DIST; ANDOVER VILLAGE DIST, while Watts Regulator Co DBA Webster Valve leads reported TRI pounds among local Form R filers. AQS median AQI 37 / peak 74 in 2024.
Burden score 49/100 (Moderate Risk) is the only weighted composite on this page. The tables below list every TRI facility, SDWIS system, and Superfund site EPA has on record for Merrimack -- not just the names called out above -- reproducing the disclosure history as filed, not a current-safety verdict. Extract current as of 2026-08-25.
Release-over-release change
What changed for Merrimack, NH: EPA TRI 2023 reporting year
Same facilities, both years
-23.0%
12 facilities that filed in 2022 and 2023
Whole inventory
-23.0%
184.0 thousand lb → 141.6 thousand lb, every facility that filed
Between the two reporting years, 1 facility filed for the first time and 3 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.
- Merrimack, NH's total reported releases fell from 184.0 thousand lb in 2022 to 141.6 thousand lb in 2023, based on EPA TRI filings.
- Merrimack, NH's land releases fell from 3.7 thousand lb in 2022 to 238 lb in 2023, based on EPA TRI filings.
- Merrimack, NH's air releases fell from 67.1 thousand lb in 2022 to 40.1 thousand lb in 2023, based on EPA TRI filings.
- Merrimack, NH's water releases fell from 426 lb in 2022 to 323 lb in 2023, based on EPA TRI filings.
Air Quality History (2020–2024)
EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.
| Year | Good | Moderate | Unhealthy (SG) | Max AQI |
|---|---|---|---|---|
| 2024 | 205 (96%) | 9 | 0 | 74 |
| 2023 | 197 (92%) | 16 | 0 | 100 |
| 2022 | 205 (97%) | 7 | 0 | 84 |
| 2021 | 200 (93%) | 13 | 1 | 101 |
| 2020 | 209 (98%) | 4 | 0 | 74 |
Source: EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)
For real-time air quality readings and pollutant breakdowns in New Hampshire, see the EPA's AirNow.gov.
Water Systems (60)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| CONCORD WATER DEPT | 44,215 | 0 |
| FRANKLIN WATER WORKS | 7,200 | 0 |
| PEMBROKE WATER WORKS | 5,200 | 0 |
| CENTRAL HOOKSETT WATER PCT | 4,650 | 0 |
| NEW LONDON SPRINGFIELD WATER | 3,250 | 0 |
| COGSWELL SPRINGS WATER WORKS | 3,000 | 0 |
| HOOKSETT VILLAGE WATER PCT | 3,000 | 0 |
| TILTON NORTHFIELD WATER DIST | 2,500 | 0 |
| CONTOOCOOK VILLAGE PCT | 1,600 | 34 |
| BEAR VIEW CROSSING | 800 | 0 |
| WARNER VILLAGE WATER DIST | 660 | 1 |
| ANDOVER VILLAGE DIST | 650 | 22 |
| HILL WATER WORKS | 600 | 0 |
| LOCHMERE VILLAGE DIST | 405 | 0 |
| CATAMOUNT HILL | 383 | 5 |
| FREEDOM HILL/PINE RIDGE EST | 370 | 25 |
| KINGS TOWNE MHP | 350 | 0 |
| VILLAGES AT LOUDON | 250 | 0 |
| OLDE TOWNE | 243 | 0 |
| EPSOM HEALTHCARE CTR | 240 | 24 |
| PLEASANT POND COOP AND CMPGRND | 218 | 1 |
| CHALK POND WATER | 208 | 0 |
| SLOPE N SHORE CLUB | 180 | 0 |
| BOW MUNICIPAL WATER SYSTEM | 150 | 0 |
| KOS MANUFACTURED HOUSING CMNTY | 137 | 1 |
| WHITTEMORE SHORES | 130 | 1 |
| SHELTERING PINES MHP | 125 | 0 |
| THE PINES AT ARUNDEL | 105 | 5 |
| STAR RIDGE | 96 | 3 |
| HIGHLANDS VILLAGE DISTRICT | 95 | 0 |
| LIBERTY RIDGE MHP | 91 | 4 |
| BRETON WOODS DEV | 90 | 1 |
| ELM BROOK VILLAGE | 90 | 7 |
| MEADOW BROOK | 75 | 2 |
| MASCOMA VALLEY COOP | 73 | 0 |
| GRIGGS MOBILE HOMES | 73 | 5 |
| WINDY HILL/SOUTH | 73 | 0 |
| KINGS GRANT | 71 | 2 |
| LADD HILL MHP | 70 | 0 |
| DARBY FIELD COMMONS | 70 | 4 |
| COLBY BROOK ESTATES | 68 | 0 |
| COUNTRY VILLAGE MHP | 66 | 5 |
| PLEASANT VALLEY PARK ESTATES | 65 | 1 |
| SODA BROOK | 64 | 2 |
| BEEBE RIVER | 63 | 4 |
| HALCYON HILL | 58 | 1 |
| POUND ROAD WATER WORKS | 53 | 1 |
| PRESIDENTIAL PINES/LOWER | 51 | 2 |
| NEWBURY ELDERLY HOUSING | 51 | 1 |
| BELLA BROOK WATER | 50 | 11 |
| WATERVILLE ACRES CONDOS | 50 | 0 |
| WINDY HILL/NORTH | 47 | 0 |
| BARRINGTON HILLS APTS/UPPER | 43 | 1 |
| CARY AND ALLEN ST DEV | 43 | 1 |
| BARRINGTON HILLS APTS/LOWER | 38 | 1 |
| MEETING HOUSE WATER | 35 | 0 |
| WILSONS MHP | 30 | 0 |
| BOROUGH RD APARTMENTS | 30 | 1 |
| CANTERBURY SPRUCES HOUSING | 25 | 0 |
| BARTON MHP | 25 | 0 |
TRI Facilities (16)
| # | Facility | Total Releases |
|---|---|---|
| 1 | Watts Regulator Co DBA Webster Valve | 472.0K lbs |
| 2 | Merrimack Station | 202.8K lbs |
| 3 | Elektrisola Inc. | 52.4K lbs |
| 4 | Kalwall Corp Flat Shee T Div | 10.6K lbs |
| 5 | Ge Co | 6.3K lbs |
| 6 | Hp Hood LLC | 1.6K lbs |
| 7 | Linde Advanced Material Technologies Inc. | 891 lbs |
| 8 | Pitco Frialator Inc | 178 lbs |
| 9 | Heat & Control | 30 lbs |
| 10 | Pike Industries Inc - Northfield | 11 lbs |
| 11 | Hooksett Crushed Stone Pike Industries Inc | 4 lbs |
| 12 | Brox Industries Inc | 0 lbs |
| 13 | Agile Magnetics | 0 lbs |
| 14 | White Mountain Imaging | 0 lbs |
| 15 | Kent Nutrition Group Inc | 0 lbs |
| 16 | Redimix Cos Inc | 0 lbs |
Cities in Merrimack (20)
Frequently Asked Questions
What is the environmental risk level in Merrimack, New Hampshire? ▼
Are there Superfund sites in Merrimack? ▼
How many toxic release facilities are in Merrimack? ▼
What is the air quality in Merrimack? ▼
Is the drinking water safe in Merrimack? ▼
What environmental agencies cover Merrimack? ▼
What does this county environmental profile show?
This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.
Read our methodology - how this data is sourced, computed, and verified.