Public water system · WY5680010
ActiveBlack Hills Nf-Cook Lake Cg
At a glance
Black Hills Nf-Cook Lake Cg (PWSID WY5680010) is an active transient non-community water system in Crook County, Wyoming. It reports serving 165 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as owned by the federal government. EPA's records list 11 violations for this system; 5 are health-based, and the most recent began in September 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
165
Service connections
1
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Black Hills Nf-Cook Lake Cg compare with other water systems in Crook County?
By EPA's size categories, Black Hills Nf-Cook Lake Cg is a very small system (500 people or fewer). Crook County has 27 active public water systems. Its population served is about half of the county average of 328 people per system, and accounts for 1.9% of the 8,854 people reported by systems filed under the county. Across Wyoming, the 775 active systems average 838 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Black Hills Nf-Cook Lake Cg is about 15% above 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. Wyoming has 352 active transient non-community water systems, 45% of the state's 775 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 585 Wyoming systems (75%) list groundwater as their primary source.
Who owns and regulates Black Hills Nf-Cook Lake Cg?
EPA lists Black Hills Nf-Cook Lake Cg as owned by the federal government. The WY state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 2 of the 27 active systems in Crook County (7.4%) are also owned by the federal government.
Does Black Hills Nf-Cook Lake Cg have drinking water violations?
EPA's records list 11 violations for this system; 5 are health-based, and the most recent began in September 2025. The violations listed here began between April 1991 and September 2025. By type: 5 contaminant level above the legal limit, 2 monitoring, 2 monitoring and reporting, 1 reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 8 as resolved and 3 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 |
|---|---|---|---|---|
| 2025-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Archived |
| 2025-07-11 | ReportingReport Sample Result/Fail Monitor (RTCR) · code 4B | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-03-07 | Public notice, recordkeeping or otherSample Siting Plan Errors (RTCR) · code 5A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2016-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1992-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1991-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
All 11 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.
Black Hills Nf-Cook Lake Cg: frequently asked questions
Who runs Black Hills Nf-Cook Lake Cg?
Black Hills Nf-Cook Lake Cg (PWSID WY5680010) is a transient non-community water system owned by the federal government. It is regulated by the WY state drinking water program.
How many people does Black Hills Nf-Cook Lake Cg serve?
Black Hills Nf-Cook Lake Cg reports serving 165 people through 1 service connection in Crook County, Wyoming.
Where does Black Hills Nf-Cook Lake Cg 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 Black Hills Nf-Cook Lake Cg have any drinking water violations?
EPA's records list 11 violations for this system; 5 are health-based, and the most recent began in September 2025. 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 Black Hills Nf-Cook Lake 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. EPA's records list 11 violations for this system; 5 are health-based, and the most recent began in September 2025. For current results, consult EPA ECHO, or the WY state drinking water program.
Where can I find Black Hills Nf-Cook Lake Cg's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Black Hills Nf-Cook Lake 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 Crook County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Devils Tower National Monument | Crook | 3,071 | Transient non-community | Groundwater |
| Sundance, City of | Crook | 1,279 | Community | Groundwater |
| Moorcroft, Town of | Crook | 1,009 | Community | Groundwater |
| Devils Tower Koa-Campstool | Crook | 516 | Transient non-community | Groundwater |
| Pine Haven, Town of | Crook | 498 | Community | Groundwater |
| Hulett, Town of | Crook | 420 | 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, “Black Hills Nf-Cook Lake Cg, PWSID WY5680010, Wyoming”, https://aquacensus.com/water-systems/wyoming/black-hills-nf-cook-lake-cg-wy5680010 (data as of October 1, 2026).