Merrimack, NH
A PlainEnviro-computed score from reported facility/violation counts, not an official EPA rating, health forecast, or population-adjusted rate. See methodology.
Environmental data for Merrimack in New Hampshire · Population: 155,018
Merrimack, NH is tracked across three EPA datasets covering 16 Toxics Release Inventory (TRI) facilities, 60 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 49/100 (Moderate Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.
Industrial disclosures inside the county total 746.8K lbs of reported toxic releases under EPCRA Section 313, while 29 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 37 and a peak AQI of 74 in 2024, with 96% of observed days rated "Good" (0–50).
All figures below draw directly from federal EPA records, TRI self-reported emissions, SDWIS compliance history, NPL Hazard Ranking System scores, and AQS daily AQI summaries, and are not adjusted, weighted, or forecast. A past violation or elevated score does not itself indicate current unsafe conditions; it documents the regulatory and disclosure history publicly filed with the U.S. Environmental Protection Agency through the most recent reporting cycle.
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 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 | Population | Violations |
|---|---|---|
| CONCORD WATER DEPT | 44,215 | 0 |
| FRANKLIN WATER WORKS | 7,000 | 0 |
| PEMBROKE WATER WORKS | 5,200 | 0 |
| CENTRAL HOOKSETT WATER PCT | 4,650 | 0 |
| COGSWELL SPRINGS WATER WORKS | 3,000 | 0 |
| HOOKSETT VILLAGE WATER PCT | 3,000 | 0 |
| NEW LONDON SPRINGFIELD WATER | 2,750 | 0 |
| TILTON NORTHFIELD WATER DIST | 2,500 | 0 |
| CONTOOCOOK VILLAGE PCT | 1,600 | 26 |
| BEAR VIEW CROSSING | 800 | 0 |
| EPSOM VILLAGE WATER DISTICT | 800 | 0 |
| WARNER VILLAGE WATER DIST | 660 | 1 |
| ANDOVER VILLAGE DIST | 650 | 20 |
| FREEDOM HILL/PINE RIDGE EST | 370 | 25 |
| KINGS TOWNE MHP | 350 | 0 |
| HILL WATER WORKS | 350 | 0 |
| VILLAGES AT LOUDON | 250 | 0 |
| EPSOM HEALTHCARE CTR | 240 | 24 |
| PLEASANT LAKE MHP | 218 | 1 |
| HOPKINTON VILLAGE PCT | 215 | 5 |
| CHALK POND WATER | 208 | 0 |
| THE MEADOWS | 200 | 0 |
| SLOPE N SHORE CLUB | 180 | 0 |
| BOW MUNICIPAL WATER SYSTEM | 150 | 0 |
| DEER MEADOWS | 150 | 0 |
| KOS MANUFACTURED HOUSING CMNTY | 137 | 1 |
| WHITTEMORE SHORES | 130 | 1 |
| SHELTERING PINES MHP | 125 | 0 |
| THE PINES AT ARUNDEL | 105 | 5 |
| WOOD HILL VILLAGE | 91 | 4 |
| BRETON WOODS DEV | 90 | 1 |
| ELM BROOK VILLAGE | 90 | 7 |
| PILLSBURY LAKE/PENINSULA | 90 | 0 |
| MEADOW BROOK | 75 | 2 |
| STAR RIDGE | 75 | 3 |
| PILLSBURY LAKE/FRANKLIN PIERCE | 75 | 3 |
| 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 |
| SODA BROOK | 64 | 2 |
| HALCYON HILL | 58 | 1 |
| WILSONS MHP | 58 | 0 |
| POUND ROAD WATER WORKS | 53 | 1 |
| PRESIDENTIAL PINES/LOWER | 51 | 2 |
| NEWBURY ELDERLY HOUSING | 51 | 0 |
| BELA 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 |
| 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 (7)
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.