Public water system · OK1010829
ActiveFoss Reservoir Mcd
At a glance
Foss Reservoir Mcd (PWSID OK1010829) is an active community water system in Custer County, Oklahoma. It reports serving 12 people through 1 service connection. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in February 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
12
Service connections
1
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Foss Reservoir Mcd compare with other water systems in Custer County?
By EPA's size categories, Foss Reservoir Mcd is a very small system (500 people or fewer). Custer County has 11 active public water systems. Its population served is well below the county average of 2,181 people per system, and accounts for less than 0.1% of the 23,986 people reported by systems filed under the county. Across Oklahoma, the 1,254 active systems average 2,907 people each. Nationally, the average active community water system reports serving 6,703 people, so Foss Reservoir Mcd 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. Oklahoma has 864 active community water systems, 69% of the state's 1,254 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 175 Oklahoma systems (14%) list surface water as their primary source.
Who owns and regulates Foss Reservoir Mcd?
EPA lists Foss Reservoir Mcd as owned by a local government. The OK state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 7 of the 11 active systems in Custer County (64%) are also owned by a local government.
Does Foss Reservoir Mcd have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in February 2021. The violations listed here began between July 2012 and February 2021. By type: 7 monitoring and reporting and 5 required treatment not met. The contaminant or rule involved most often is Carbon, total (5 of them). EPA lists 8 as resolved and 4 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 |
|---|---|---|---|---|
| 2021-02-01 | Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38 | Interim Enhanced Surface Water Treatment Rulecode 0300 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross Beta Particle Activitycode 4100 | No | Archived |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Uraniumcode 4006 | No | Archived |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Archived |
| 2013-12-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2013-12-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2013-07-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | Resolved |
| 2013-04-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | Resolved |
| 2013-01-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | Resolved |
| 2012-10-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | Resolved |
| 2012-07-01 | Required treatment not metTreatment Technique Precursor Removal · code 46 | Carbon, totalcode 2920 | Yes | 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.
Foss Reservoir Mcd: frequently asked questions
Who runs Foss Reservoir Mcd?
Foss Reservoir Mcd (PWSID OK1010829) is a community water system owned by a local government. It is regulated by the OK state drinking water program.
How many people does Foss Reservoir Mcd serve?
Foss Reservoir Mcd reports serving 12 people through 1 service connection in Custer County, Oklahoma.
Where does Foss Reservoir Mcd get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Foss Reservoir Mcd have any drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in February 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 Foss Reservoir Mcd'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, 5 are health-based, and the most recent began in February 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the OK state drinking water program.
Where can I find Foss Reservoir Mcd's water quality report?
As a community water system, Foss Reservoir Mcd 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 Custer County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Weatherford | Custer | 10,833 | Community | Groundwater |
| Clinton | Custer | 8,883 | Community | Surface water |
| Thomas | Custer | 1,238 | Community | Groundwater |
| Custer County Rwd #3 | Custer | 960 | Community | Groundwater |
| Arapaho | Custer | 748 | Community | Purchased surface water |
| Frontier Development Auth | Custer | 437 | Community | Purchased 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, “Foss Reservoir Mcd, PWSID OK1010829, Oklahoma”, https://aquacensus.com/water-systems/oklahoma/foss-reservoir-mcd-ok1010829 (data as of October 1, 2026).