Public water system · NH2372020
ActiveHidden Valley/Mason
At a glance
Hidden Valley/Mason (PWSID NH2372020) is an active community water system in Carroll County, New Hampshire. It reports serving 298 people through 127 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
298
Service connections
127
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hidden Valley/Mason compare with other water systems in Carroll County?
By EPA's size categories, Hidden Valley/Mason is a very small system (500 people or fewer). Carroll County has 366 active public water systems. Its population served is about 35% above the county average of 221 people per system, and accounts for 0.4% of the 81,013 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 Hidden Valley/Mason 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 Hidden Valley/Mason?
EPA lists Hidden Valley/Mason as privately owned. 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. 328 of the 366 active systems in Carroll County (90%) are also privately owned.
Does Hidden Valley/Mason have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 2024. The violations listed here began between January 1994 and October 2024. By type: 8 monitoring and reporting, 2 contaminant level above the legal limit, 1 reporting and 1 required treatment not met. The contaminant or rule involved most often is Revised Total Coliform Rule (2 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 |
|---|---|---|---|---|
| 2024-10-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2016-12-01 | ReportingReporting, Assessment Forms (RTCR) · code 4A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2016-12-01 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2011-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2010-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitritecode 1041 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,2-Trichloroethanecode 2985 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Trichloroethylenecode 2984 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 2,4-Dcode 2105 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2,4-Trichlorobenzenecode 2378 | No | Resolved |
| 1994-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlordanecode 2959 | 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.
Hidden Valley/Mason: frequently asked questions
Who runs Hidden Valley/Mason?
Hidden Valley/Mason (PWSID NH2372020) is a community water system privately owned. It is regulated by the NH state drinking water program.
How many people does Hidden Valley/Mason serve?
Hidden Valley/Mason reports serving 298 people through 127 service connections in Carroll County, New Hampshire.
Where does Hidden Valley/Mason 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 Hidden Valley/Mason have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in October 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 Hidden Valley/Mason'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, 3 are health-based, and the most recent began in October 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 Hidden Valley/Mason's water quality report?
As a community water system, Hidden Valley/Mason 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 Carroll County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Wolfeboro Water and Sewer | Carroll | 6,000 | Community | Surface water |
| North Conway Water Pct | Carroll | 5,500 | Community | Groundwater |
| Lower Bartlett Water Pct | Carroll | 3,850 | Community | Groundwater |
| Conway Water and Sewer | Carroll | 2,745 | Community | Groundwater |
| Paradise Shores | Carroll | 2,060 | Community | Groundwater |
| Sanbornville Water Dept | Carroll | 1,425 | 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, “Hidden Valley/Mason, PWSID NH2372020, New Hampshire”, https://aquacensus.com/water-systems/new-hampshire/hidden-valley-mason-nh2372020 (data as of October 1, 2026).