Public water system · NH1951010
ActivePortsmouth Water Works
At a glance
Portsmouth Water Works (PWSID NH1951010) is an active community water system in Rockingham County, New Hampshire. It reports serving 33,000 people through 7,200 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in July 2014.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
33,000
Service connections
7,200
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Portsmouth Water Works compare with other water systems in Rockingham County?
By EPA's size categories, Portsmouth Water Works is a large system (10,001 to 100,000 people). Rockingham County has 554 active public water systems, and Portsmouth Water Works is the 2nd-largest of them by population served. Its population served is about 67 times the county average of 492 people per system, and accounts for 12% 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 Portsmouth Water Works is about 4.9 times 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 39 New Hampshire systems (1.6%) list surface water as their primary source.
Who owns and regulates Portsmouth Water Works?
EPA lists Portsmouth Water Works 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 Portsmouth Water Works have drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in July 2014. The violations listed here began between December 1998 and July 2014. By type: 7 required treatment not met and 5 contaminant level above the legal limit. The contaminant or rule involved most often is Interim Enhanced Surface Water Treatment Rule (4 of them). EPA lists 12 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 |
|---|---|---|---|---|
| 2014-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2008-01-01 | Required treatment not metSingle Turbidity Exceed (Enhanced SWTR) · code 43 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2007-03-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2006-07-01 | Required treatment not metSingle Turbidity Exceed (Enhanced SWTR) · code 43 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2005-10-01 | Required treatment not metSingle Turbidity Exceed (Enhanced SWTR) · code 43 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2005-10-01 | Required treatment not metMonthly Turbidity Exceed (Enhanced SWTR) · code 44 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2003-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2003-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2003-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2001-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2001-07-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 1998-12-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
The 12 most recent 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.
Portsmouth Water Works: frequently asked questions
Who runs Portsmouth Water Works?
Portsmouth Water Works (PWSID NH1951010) is a community water system owned by a local government. It is regulated by the NH state drinking water program.
How many people does Portsmouth Water Works serve?
Portsmouth Water Works reports serving 33,000 people through 7,200 service connections in Rockingham County, New Hampshire.
Where does Portsmouth Water Works get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Portsmouth Water Works have any drinking water violations?
Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in July 2014. 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 Portsmouth Water Works' 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. Of the 12 most recent violations in EPA's records, 12 are health-based, and the most recent began in July 2014. For current results, consult the system's annual water quality report, EPA ECHO, or the NH state drinking water program.
Where can I find Portsmouth Water Works' water quality report?
As a community water system, Portsmouth Water Works 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 |
| Salem Water Dept | Rockingham | 21,000 | Community | Surface water |
| Derry Water Dept | Rockingham | 17,370 | Community | Purchased 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, “Portsmouth Water Works, PWSID NH1951010, New Hampshire”, https://aquacensus.com/water-systems/new-hampshire/portsmouth-water-works-nh1951010 (data as of October 1, 2026).