Public water system · NH1141020

Active

Emerald Lake

At a glance

Emerald Lake (PWSID NH1141020) is an active community water system in Hillsborough County, New Hampshire. It reports serving 1,300 people through 528 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2024.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

1,300

Service connections

528

Primary source

Groundwater

System type

CWS

Community water system

System record

PWSIDNH1141020

System typeCommunity water system

Activity statusActive

Population served1,300

Service connections528

Primary water sourceGroundwater

Owner typeLocal government

Primacy agencyNH state drinking water program

City servedHillsborough

StateNew Hampshire

ZIP—

CountyHillsborough County

How does Emerald Lake compare with other water systems in Hillsborough County?

By EPA's size categories, Emerald Lake is a small system (501 to 3,300 people). Hillsborough County has 279 active public water systems. Its population served is roughly in line with the county average of 1,206 people per system, and accounts for 0.4% of the 336,507 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 Emerald Lake is well below 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. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,374 New Hampshire systems (97%) list groundwater as their primary source.

Who owns and regulates Emerald Lake?

EPA lists Emerald Lake 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. 36 of the 279 active systems in Hillsborough County (13%) are also owned by a local government.

Does Emerald Lake have drinking water violations?

Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2024. The violations listed here began between July 2016 and July 2024. By type: 4 contaminant level above the legal limit, 3 monitoring and reporting, 2 public notice, recordkeeping or other, 1 reporting, 1 monitoring and 1 required treatment not met. The contaminant or rule involved most often is Arsenic (4 of them). EPA lists 11 as resolved and 1 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.

Began	Violation	Contaminant or rule	Health-based	Status
2024-07-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Resolved
2024-07-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Resolved
2021-11-10	ReportingReport Sample Result/Fail Monitor (RTCR) · code 4B	Revised Total Coliform Rulecode 8000	No	Resolved
2021-10-01	MonitoringMonitoring, Routine (RTCR) · code 3A	Revised Total Coliform Rulecode 8000	No	Resolved
2020-10-02	Required treatment not metFailure To Address Deficiency · code 45	Groundwater Rulecode 0700	Yes	Unaddressed
2020-01-23	Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75	Public Noticecode 7500	No	Resolved
2020-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Arseniccode 1005	Yes	Resolved
2019-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Arseniccode 1005	Yes	Resolved
2019-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Arseniccode 1005	Yes	Resolved
2019-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Arseniccode 1005	Yes	Resolved
2016-09-15	Monitoring and reportingMonitoring, Source Water (GWR) · code 34	E. colicode 3014	No	Resolved
2016-07-01	Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71	Consumer Confidence Rulecode 7000	No	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.

Emerald Lake: frequently asked questions

Who runs Emerald Lake?

Emerald Lake (PWSID NH1141020) is a community water system owned by a local government. It is regulated by the NH state drinking water program.

How many people does Emerald Lake serve?

Emerald Lake reports serving 1,300 people through 528 service connections in Hillsborough County, New Hampshire.

Where does Emerald Lake get its water?

EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.

Does Emerald Lake have any drinking water violations?

Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2024. 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 Emerald Lake'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. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the NH state drinking water program.

Where can I find Emerald Lake's water quality report?

As a community water system, Emerald Lake 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 Hillsborough County

Water system	County	Population served	Type	Source
Manchester Water Works	Hillsborough	123,500	Community	Surface water
Pennichuck Water Works	Hillsborough	88,853	Community	Surface water
Merrimack Village Dist	Hillsborough	25,500	Community	Groundwater
Hudson Water Dept	Hillsborough	16,700	Community	Groundwater
Milford Water Utilities Dept	Hillsborough	9,500	Community	Purchased surface water
Litchfield	Hillsborough	6,920	Community	Purchased surface water

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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, “Emerald Lake, PWSID NH1141020, New Hampshire”, https://aquacensus.com/water-systems/new-hampshire/emerald-lake-nh1141020 (data as of October 1, 2026).