Public water system · KS2020102
ActiveMahaska, City of
At a glance
City of Mahaska (PWSID KS2020102) is an active community water system in Washington County, Kansas. It reports serving 44 people through 42 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, 6 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
44
Service connections
42
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Mahaska compare with other water systems in Washington County?
By EPA's size categories, City of Mahaska is a very small system (500 people or fewer). Washington County has 12 active public water systems. Its population served is well below the county average of 438 people per system, and accounts for 0.8% of the 5,258 people reported by systems filed under the county. Across Kansas, the 1,041 active systems average 2,800 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Mahaska 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. Kansas has 863 active community water systems, 83% of the state's 1,041 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 587 Kansas systems (56%) list groundwater as their primary source.
Who owns and regulates City of Mahaska?
EPA lists City of Mahaska as owned by a local government. The KS state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 12 of the 12 active systems in Washington County (100%) are also owned by a local government.
Does City of Mahaska have drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in July 2025. The violations listed here began between December 2013 and July 2025. By type: 5 contaminant level above the legal limit, 4 monitoring and reporting, 1 reporting, 1 monitoring and 1 required treatment not met. The contaminant or rule involved most often is Combined Radium (-226 and -228) (5 of them). EPA lists 9 as resolved and 3 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-02 | ReportingNotification, Known or Potential LSL · code 4H | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2024-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2024-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2024-05-28 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2020-12-31 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2017-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2015-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2014-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2014-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2014-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2013-12-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | 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.
City of Mahaska: frequently asked questions
Who runs City of Mahaska?
City of Mahaska (PWSID KS2020102) is a community water system owned by a local government. It is regulated by the KS state drinking water program.
How many people does City of Mahaska serve?
City of Mahaska reports serving 44 people through 42 service connections in Washington County, Kansas.
Where does City of Mahaska 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 City of Mahaska have any drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are 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 City of Mahaska'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, 6 are 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 KS state drinking water program.
Where can I find City of Mahaska's water quality report?
As a community water system, City of Mahaska 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 Washington County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Washington Co Rwd 1 | Washington | 1,093 | Community | Groundwater |
| Washington, City of | Washington | 1,065 | Community | Groundwater |
| Hanover, City of | Washington | 689 | Community | Purchased groundwater |
| Washington Co Rwd 2 | Washington | 673 | Community | Groundwater |
| Clifton, City of | Washington | 455 | Community | Groundwater |
| Linn, City of | Washington | 382 | 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, “Mahaska, City of, PWSID KS2020102, Kansas”, https://aquacensus.com/water-systems/kansas/mahaska-city-of-ks2020102 (data as of October 1, 2026).