Public water system · MO5240546
ActiveTwin Oaks Harbor
At a glance
Twin Oaks Harbor (PWSID MO5240546) is an active community water system in St. Clair County, Missouri. It reports serving 50 people through 114 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 6 violations for this system; none is health-based, and the most recent began in July 2014.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
50
Service connections
114
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Twin Oaks Harbor compare with other water systems in St. Clair County?
By EPA's size categories, Twin Oaks Harbor is a very small system (500 people or fewer). St. Clair County has 14 active public water systems. Its population served is well below the county average of 449 people per system, and accounts for 0.8% of the 6,287 people reported by systems filed under the county. Across Missouri, the 2,943 active systems average 2,049 people each. Nationally, the average active community water system reports serving 6,703 people, so Twin Oaks Harbor 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. Missouri has 1,612 active community water systems, 55% of the state's 2,943 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,521 Missouri systems (86%) list groundwater as their primary source.
Who owns and regulates Twin Oaks Harbor?
EPA lists Twin Oaks Harbor as privately owned. The MO 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 14 active systems in St. Clair County (50%) are also privately owned.
Does Twin Oaks Harbor have drinking water violations?
EPA's records list 6 violations for this system; none is health-based, and the most recent began in July 2014. The violations listed here began between November 1994 and July 2014. By type: 3 public notice, recordkeeping or other and 3 monitoring and reporting. The contaminant or rule involved most often is Consumer Confidence Rule (3 of them). EPA lists 6 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 |
|---|---|---|---|---|
| 2014-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2013-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2012-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2011-09-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1994-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 6 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.
Twin Oaks Harbor: frequently asked questions
Who runs Twin Oaks Harbor?
Twin Oaks Harbor (PWSID MO5240546) is a community water system privately owned. It is regulated by the MO state drinking water program.
How many people does Twin Oaks Harbor serve?
Twin Oaks Harbor reports serving 50 people through 114 service connections in St. Clair County, Missouri.
Where does Twin Oaks Harbor 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 Twin Oaks Harbor have any drinking water violations?
EPA's records list 6 violations for this system; none is health-based, and the most recent began in July 2014. 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 Twin Oaks Harbor'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 6 violations for this system; none is health-based, and the most recent began in July 2014. For current results, consult the system's annual water quality report, EPA ECHO, or the MO state drinking water program.
Where can I find Twin Oaks Harbor's water quality report?
As a community water system, Twin Oaks Harbor 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 St. Clair County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| H Roe Bartle Scout Reservation | St. Clair | 1,800 | Transient non-community | Groundwater |
| Appleton City Pws | St. Clair | 1,050 | Community | Purchased surface water |
| Osceola Pws | St. Clair | 947 | Community | Groundwater |
| Lowry City Pws | St. Clair | 640 | Community | Groundwater |
| Osceola Public School | St. Clair | 575 | Non-transient non-community | Groundwater |
| Osceola Cheese Company | St. Clair | 500 | Transient non-community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Twin Oaks Harbor, PWSID MO5240546, Missouri”, https://aquacensus.com/water-systems/missouri/twin-oaks-harbor-mo5240546 (data as of October 1, 2026).