Public water system · NH0611010
ActiveDerry Water Dept
At a glance
Derry Water Dept (PWSID NH0611010) is an active community water system in Rockingham County, New Hampshire. It reports serving 17,370 people through 4,302 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 3 violations for this system; all are health-based, and the most recent began in August 2004.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
17,370
Service connections
4,302
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Derry Water Dept compare with other water systems in Rockingham County?
By EPA's size categories, Derry Water Dept is a large system (10,001 to 100,000 people). Rockingham County has 554 active public water systems, and Derry Water Dept is the 4th-largest of them by population served. Its population served is about 35 times the county average of 492 people per system, and accounts for 6.4% of the 272,726 people reported by systems filed under the county. Across New Hampshire, the 2,450 active systems average 508 people each. Nationally, the average active community water system reports serving 6,703 people, so Derry Water Dept is about 159% above that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. New Hampshire has 706 active community water systems, 29% of the state's 2,450 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 27 New Hampshire systems (1.1%) list purchased surface water as their primary source.
Who owns and regulates Derry Water Dept?
EPA lists Derry Water Dept as owned by a local government. The NH state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 70 of the 554 active systems in Rockingham County (13%) are also owned by a local government.
Does Derry Water Dept have drinking water violations?
EPA's records list 3 violations for this system; all are health-based, and the most recent began in August 2004. The violations listed here began between June 1998 and August 2004. By type: 3 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 3 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2004-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 3 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Derry Water Dept: frequently asked questions
Who runs Derry Water Dept?
Derry Water Dept (PWSID NH0611010) is a community water system owned by a local government. It is regulated by the NH state drinking water program.
How many people does Derry Water Dept serve?
Derry Water Dept reports serving 17,370 people through 4,302 service connections in Rockingham County, New Hampshire.
Where does Derry Water Dept get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Derry Water Dept have any drinking water violations?
EPA's records list 3 violations for this system; all are health-based, and the most recent began in August 2004. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Derry Water Dept's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 3 violations for this system; all are health-based, and the most recent began in August 2004. For current results, consult the system's annual water quality report, EPA ECHO, or the NH state drinking water program.
Where can I find Derry Water Dept's water quality report?
As a community water system, Derry Water Dept must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Rockingham County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Aquarion Water/Nh | Rockingham | 34,000 | Community | Groundwater |
| Portsmouth Water Works | Rockingham | 33,000 | Community | Surface water |
| Salem Water Dept | Rockingham | 21,000 | Community | Surface water |
| Seabrook Water Dept | Rockingham | 14,000 | Community | Groundwater |
| Exeter Water Dept | Rockingham | 12,236 | Community | Surface water |
| Pease Trade Port | Rockingham | 9,900 | Community | Groundwater |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Derry Water Dept, PWSID NH0611010, New Hampshire”, https://aquacensus.com/water-systems/new-hampshire/derry-water-dept-nh0611010 (data as of October 1, 2026).