Public water system · MD1041112
ActiveCalvert Marina/ Hidden Harbor LLC
At a glance
Calvert Marina/ Hidden Harbor LLC (PWSID MD1041112) is an active transient non-community water system in Calvert County, Maryland. It reports serving 60 people through 5 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 4 violations for this system; all are health-based, and the most recent began in October 2013.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
60
Service connections
5
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Calvert Marina/ Hidden Harbor LLC compare with other water systems in Calvert County?
By EPA's size categories, Calvert Marina/ Hidden Harbor LLC is a very small system (500 people or fewer). Calvert County has 203 active public water systems. Its population served is well below the county average of 384 people per system, and accounts for less than 0.1% of the 77,996 people reported by systems filed under the county. Across Maryland, the 2,992 active systems average 1,947 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Calvert Marina/ Hidden Harbor LLC is about 58% below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Maryland has 2,079 active transient non-community water systems, 69% of the state's 2,992 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,870 Maryland systems (96%) list groundwater as their primary source.
Who owns and regulates Calvert Marina/ Hidden Harbor LLC?
EPA lists Calvert Marina/ Hidden Harbor LLC as privately owned. The MD state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 160 of the 203 active systems in Calvert County (79%) are also privately owned.
Does Calvert Marina/ Hidden Harbor LLC have drinking water violations?
EPA's records list 4 violations for this system; all are health-based, and the most recent began in October 2013. The violations listed here began between July 1991 and October 2013. By type: 4 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 3 as resolved and 1 as archived. 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. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2013-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1991-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
All 4 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.
Calvert Marina/ Hidden Harbor LLC: frequently asked questions
Who runs Calvert Marina/ Hidden Harbor LLC?
Calvert Marina/ Hidden Harbor LLC (PWSID MD1041112) is a transient non-community water system privately owned. It is regulated by the MD state drinking water program.
How many people does Calvert Marina/ Hidden Harbor LLC serve?
Calvert Marina/ Hidden Harbor LLC reports serving 60 people through 5 service connections in Calvert County, Maryland.
Where does Calvert Marina/ Hidden Harbor LLC 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 Calvert Marina/ Hidden Harbor LLC have any drinking water violations?
EPA's records list 4 violations for this system; all are health-based, and the most recent began in October 2013. 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 Calvert Marina/ Hidden Harbor LLC'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 4 violations for this system; all are health-based, and the most recent began in October 2013. For current results, consult EPA ECHO, or the MD state drinking water program.
Where can I find Calvert Marina/ Hidden Harbor LLC's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Calvert Marina/ Hidden Harbor LLC is a transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Calvert County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Chesapeake Ranch Estates | Calvert | 9,500 | Community | Groundwater |
| Town of Chesapeake Beach | Calvert | 5,000 | Community | Groundwater |
| Prince Frederick | Calvert | 4,371 | Community | Groundwater |
| Solomons | Calvert | 3,811 | Community | Groundwater |
| Town of North Beach | Calvert | 3,000 | Community | Groundwater |
| Northern Middle & High Schools | Calvert | 2,470 | Non-transient non-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, “Calvert Marina/ Hidden Harbor LLC, PWSID MD1041112, Maryland”, https://aquacensus.com/water-systems/maryland/calvert-marina-hidden-harbor-llc-md1041112 (data as of October 1, 2026).