Public water system · IA6739434
ActiveOnawa Koa
At a glance
Onawa Koa (PWSID IA6739434) is an active transient non-community water system in Monona County, Iowa. It reports serving 250 people through 100 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in April 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
250
Service connections
100
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Onawa Koa compare with other water systems in Monona County?
By EPA's size categories, Onawa Koa is a very small system (500 people or fewer). Monona County has 14 active public water systems, and Onawa Koa is the 5th-largest of them by population served. Its population served is about half of the county average of 462 people per system, and accounts for 3.9% of the 6,465 people reported by systems filed under the county. Across Iowa, the 1,828 active systems average 1,718 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Onawa Koa is about 74% 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. Iowa has 626 active transient non-community water systems, 34% of the state's 1,828 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,502 Iowa systems (82%) list groundwater as their primary source.
Who owns and regulates Onawa Koa?
EPA lists Onawa Koa as privately owned. The IA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 4 of the 14 active systems in Monona County (29%) are also privately owned.
Does Onawa Koa have drinking water violations?
EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in April 2024. The violations listed here began between July 1988 and April 2024. By type: 5 monitoring and reporting, 1 required treatment not met and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 7 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 |
|---|---|---|---|---|
| 2024-04-01 | Required treatment not metTreatment Technique Startup Procedures (RTCR) · code 2D | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2021-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2010-07-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2006-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2001-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1988-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
All 7 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.
Onawa Koa: frequently asked questions
Who runs Onawa Koa?
Onawa Koa (PWSID IA6739434) is a transient non-community water system privately owned. It is regulated by the IA state drinking water program.
How many people does Onawa Koa serve?
Onawa Koa reports serving 250 people through 100 service connections in Monona County, Iowa.
Where does Onawa Koa 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 Onawa Koa have any drinking water violations?
EPA's records list 7 violations for this system; 1 is health-based, and the most recent began in April 2024. 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 Onawa Koa'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 7 violations for this system; 1 is health-based, and the most recent began in April 2024. For current results, consult EPA ECHO, or the IA state drinking water program.
Where can I find Onawa Koa's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Onawa Koa 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 Monona County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Onawa Municipal Water Plant | Monona | 2,906 | Community | Groundwater |
| Mapleton Municipal Water Plant | Monona | 1,124 | Community | Groundwater |
| Whiting Water Supply | Monona | 727 | Community | Groundwater |
| Ute Water Supply | Monona | 338 | Community | Groundwater |
| Timber Ridge Lodge Recreation, Ltd. | Monona | 250 | Transient non-community | Groundwater |
| Blencoe Municipal Waterworks | Monona | 224 | 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, “Onawa Koa, PWSID IA6739434, Iowa”, https://aquacensus.com/water-systems/iowa/onawa-koa-ia6739434 (data as of October 1, 2026).