Public water system · CO0342500

Active

Mavreeso Cg

At a glance

Mavreeso Cg (PWSID CO0342500) is an active transient non-community water system in Dolores County, Colorado. It reports serving 25 people through 1 service connection. Its primary water source is groundwater under influence of surface water, and EPA lists it as owned by the federal government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2021.

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

Population served

Service connections

Primary source

Groundwater under influence of surface water

System type

TNCWS

Transient non-community water system

System record

PWSIDCO0342500

System typeTransient non-community water system

Activity statusActive

Population served25

Service connections1

Primary water sourceGroundwater under influence of surface water

Owner typeFederal government

Primacy agencyCO state drinking water program

City served—

StateColorado

ZIP—

CountyDolores County

How does Mavreeso Cg compare with other water systems in Dolores County?

By EPA's size categories, Mavreeso Cg is a very small system (500 people or fewer). Dolores County has 6 active public water systems, and Mavreeso Cg is the 5th-largest of them by population served. Its population served is well below the county average of 237 people per system, and accounts for 1.8% of the 1,420 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 Mavreeso Cg is well 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. Colorado has 956 active transient non-community water systems, 43% of the state's 2,207 active systems. Groundwater under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules. 166 Colorado systems (7.5%) list groundwater under influence of surface water as their primary source.

Who owns and regulates Mavreeso Cg?

EPA lists Mavreeso Cg as owned by the federal government. 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. 3 of the 6 active systems in Dolores County (50%) are also owned by the federal government.

Does Mavreeso Cg have drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2021. The violations listed here began between May 2019 and October 2021. By type: 11 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Surface Water Treatment Rule (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
2021-10-10	Public notice, recordkeeping or otherPublic Notification Violation without NPDWR Violation · code 76	Public Noticecode 7500	No	Resolved
2021-09-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Resolved
2021-09-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2020-09-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2020-09-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Resolved
2019-09-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2019-09-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Resolved
2019-08-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Resolved
2019-08-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2019-07-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2019-07-01	Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38	Interim Enhanced Surface Water Treatment Rulecode 0300	No	Resolved
2019-05-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	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.

Mavreeso Cg: frequently asked questions

Who runs Mavreeso Cg?

Mavreeso Cg (PWSID CO0342500) is a transient non-community water system owned by the federal government. It is regulated by the CO state drinking water program.

How many people does Mavreeso Cg serve?

Mavreeso Cg reports serving 25 people through 1 service connection in Dolores County, Colorado.

Where does Mavreeso Cg get its water?

EPA SDWIS lists this system's primary water source as groundwater under influence of surface water. Groundwater under the influence of surface water is well or spring water that the regulator has found to be affected by nearby surface water, so it is regulated under the surface-water treatment rules.

Does Mavreeso Cg have any drinking water violations?

Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2021. 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 Mavreeso Cg'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, none is health-based, and the most recent began in October 2021. For current results, consult EPA ECHO, or the CO state drinking water program.

Where can I find Mavreeso Cg's water quality report?

The annual Consumer Confidence Report requirement applies to community water systems. Mavreeso Cg 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 Dolores County

Water system	County	Population served	Type	Source
Dove Creek Town of	Dolores	850	Community	Surface water
Rico Town of	Dolores	437	Community	Groundwater
Dunton Hot Springs Inc.	Dolores	47	Non-transient non-community	Groundwater
Cayton Cg	Dolores	36	Transient non-community	Groundwater
West Dolores Campground	Dolores	25	Transient non-community	Groundwater under influence of 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, “Mavreeso Cg, PWSID CO0342500, Colorado”, https://aquacensus.com/water-systems/colorado/mavreeso-cg-co0342500 (data as of October 1, 2026).