Public water system · CO0235501
ActiveEstes Park Cg at Marys Lake
At a glance
Estes Park Cg at Marys Lake (PWSID CO0235501) is an active transient non-community water system in Larimer County, Colorado. It reports serving 700 people through 95 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, one is health-based, and the most recent began in July 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
700
Service connections
95
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Estes Park Cg at Marys Lake compare with other water systems in Larimer County?
By EPA's size categories, Estes Park Cg at Marys Lake is a small system (501 to 3,300 people). Larimer County has 134 active public water systems. Its population served is well below the county average of 3,842 people per system, and accounts for 0.1% of the 514,860 people reported by systems filed under the county. Across Colorado, the 2,207 active systems average 3,400 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Estes Park Cg at Marys Lake is about 4.9 times 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. Colorado has 956 active transient non-community water systems, 43% of the state's 2,207 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,437 Colorado systems (65%) list groundwater as their primary source.
Who owns and regulates Estes Park Cg at Marys Lake?
EPA lists Estes Park Cg at Marys Lake as privately owned. The CO state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 86 of the 134 active systems in Larimer County (64%) are also privately owned.
Does Estes Park Cg at Marys Lake have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2023. The violations listed here began between January 2004 and July 2023. By type: 10 monitoring and reporting, 1 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Nitrate (6 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 |
|---|---|---|---|---|
| 2023-07-27 | Public notice, recordkeeping or otherSample Siting Plan Errors (RTCR) · code 5A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2014-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2013-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2013-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2012-06-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2011-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2010-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2009-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2006-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2004-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | 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.
Estes Park Cg at Marys Lake: frequently asked questions
Who runs Estes Park Cg at Marys Lake?
Estes Park Cg at Marys Lake (PWSID CO0235501) is a transient non-community water system privately owned. It is regulated by the CO state drinking water program.
How many people does Estes Park Cg at Marys Lake serve?
Estes Park Cg at Marys Lake reports serving 700 people through 95 service connections in Larimer County, Colorado.
Where does Estes Park Cg at Marys 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 Estes Park Cg at Marys Lake have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2023. 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 Estes Park Cg at Marys 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, one is health-based, and the most recent began in July 2023. For current results, consult EPA ECHO, or the CO state drinking water program.
Where can I find Estes Park Cg at Marys Lake's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Estes Park Cg at Marys Lake 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 Larimer County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Ft Collins City of | Larimer | 179,901 | Community | Surface water |
| Loveland City of | Larimer | 91,077 | Community | Surface water |
| Ft Collins Loveland Wd | Larimer | 63,532 | Community | Purchased surface water |
| East Larimer County Wd | Larimer | 27,944 | Community | Purchased surface water |
| Csu Main and West Housing Campus | Larimer | 27,375 | Community | Purchased surface water |
| Little Thompson Wd | Larimer | 25,654 | Community | Purchased surface water |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Estes Park Cg at Marys Lake, PWSID CO0235501, Colorado”, https://aquacensus.com/water-systems/colorado/estes-park-cg-at-marys-lake-co0235501 (data as of October 1, 2026).