Public water system · OK2003201
ActiveCalvin
At a glance
Calvin (PWSID OK2003201) is an active community water system in Hughes County, Oklahoma. It reports serving 300 people through 138 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
300
Service connections
138
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Calvin compare with other water systems in Hughes County?
By EPA's size categories, Calvin is a very small system (500 people or fewer). Hughes County has 10 active public water systems. Its population served is well below the county average of 1,283 people per system, and accounts for 2.3% of the 12,826 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 Calvin 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. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 701 Oklahoma systems (56%) list groundwater as their primary source.
Who owns and regulates Calvin?
EPA lists Calvin 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. 9 of the 10 active systems in Hughes County (90%) are also owned by a local government.
Does Calvin 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 2025. The violations listed here began between July 2014 and July 2025. By type: 6 monitoring and reporting, 5 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Consumer Confidence Rule (5 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 |
|---|---|---|---|---|
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-10-02 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross Beta Particle Activitycode 4100 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 2021-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Uraniumcode 4006 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitrate-Nitritecode 1038 | No | Resolved |
| 2017-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-05-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2015-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | 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.
Calvin: frequently asked questions
Who runs Calvin?
Calvin (PWSID OK2003201) is a community water system owned by a local government. It is regulated by the OK state drinking water program.
How many people does Calvin serve?
Calvin reports serving 300 people through 138 service connections in Hughes County, Oklahoma.
Where does Calvin 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 Calvin 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 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 Calvin'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 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the OK state drinking water program.
Where can I find Calvin's water quality report?
As a community water system, Calvin 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 Hughes County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Holdenville | Hughes | 4,732 | Community | Surface water |
| Hughes Co. Rwd #6 (Gerty) | Hughes | 2,180 | Community | Groundwater |
| Wetumka | Hughes | 1,451 | Community | Surface water |
| Hughes Co. Rwd #1 | Hughes | 1,225 | Community | Groundwater |
| Hughes Co. Rwd #2 | Hughes | 1,145 | Community | Groundwater |
| Hughes Co. Rwd #5 | Hughes | 800 | 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, “Calvin, PWSID OK2003201, Oklahoma”, https://aquacensus.com/water-systems/oklahoma/calvin-ok2003201 (data as of October 1, 2026).