Public water system · IA5200861
ActiveTwin Valley Lakes Improvement Assn
At a glance
Twin Valley Lakes Improvement Assn (PWSID IA5200861) is an active community water system in Johnson County, Iowa. It reports serving 100 people through 40 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
100
Service connections
40
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Twin Valley Lakes Improvement Assn compare with other water systems in Johnson County?
By EPA's size categories, Twin Valley Lakes Improvement Assn is a very small system (500 people or fewer). Johnson County has 125 active public water systems. Its population served is well below the county average of 1,384 people per system, and accounts for less than 0.1% of the 172,955 people reported by systems filed under the county. Across Iowa, the 1,828 active systems average 1,718 people each. Nationally, the average active community water system reports serving 6,703 people, so Twin Valley Lakes Improvement Assn 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. Iowa has 1,084 active community water systems, 59% 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 Twin Valley Lakes Improvement Assn?
EPA lists Twin Valley Lakes Improvement Assn 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. 102 of the 125 active systems in Johnson County (82%) are also privately owned.
Does Twin Valley Lakes Improvement Assn have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in July 2025. The violations listed here began between July 2008 and July 2025. By type: 5 monitoring and reporting, 4 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (5 of them). EPA lists 10 as resolved and 2 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 |
|---|---|---|---|---|
| 2025-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Archived |
| 2025-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Archived |
| 2022-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2020-06-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2019-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-12-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2012-01-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2010-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2009-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2008-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | 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.
Twin Valley Lakes Improvement Assn: frequently asked questions
Who runs Twin Valley Lakes Improvement Assn?
Twin Valley Lakes Improvement Assn (PWSID IA5200861) is a community water system privately owned. It is regulated by the IA state drinking water program.
How many people does Twin Valley Lakes Improvement Assn serve?
Twin Valley Lakes Improvement Assn reports serving 100 people through 40 service connections in Johnson County, Iowa.
Where does Twin Valley Lakes Improvement Assn 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 Valley Lakes Improvement Assn have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 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 Twin Valley Lakes Improvement Assn'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, 4 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 IA state drinking water program.
Where can I find Twin Valley Lakes Improvement Assn's water quality report?
As a community water system, Twin Valley Lakes Improvement Assn 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 Johnson County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Iowa City Water Department | Johnson | 68,753 | Community | Surface water |
| University Water System | Johnson | 26,684 | Community | Surface water |
| North Liberty Water Supply | Johnson | 23,276 | Community | Groundwater |
| Coralville Muni Water System | Johnson | 22,318 | Community | Groundwater |
| Tiffin Water Supply | Johnson | 7,577 | Community | Groundwater |
| Solon Water Dept | Johnson | 3,018 | 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, “Twin Valley Lakes Improvement Assn, PWSID IA5200861, Iowa”, https://aquacensus.com/water-systems/iowa/twin-valley-lakes-improvement-assn-ia5200861 (data as of October 1, 2026).