Public water system · IA9545044
ActiveLake Mills Municipal Water Dept-South
At a glance
Lake Mills Municipal Water Dept-South (PWSID IA9545044) is an active community water system in Winnebago County, Iowa. It reports serving 2,158 people through 1,116 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in April 2001.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,158
Service connections
1,116
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Lake Mills Municipal Water Dept-South compare with other water systems in Winnebago County?
By EPA's size categories, Lake Mills Municipal Water Dept-South is a small system (501 to 3,300 people). Winnebago County has 19 active public water systems, and Lake Mills Municipal Water Dept-South is the 2nd-largest of them by population served. Its population served is about 4.3 times the county average of 496 people per system, and accounts for 23% of the 9,425 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 Lake Mills Municipal Water Dept-South 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 Lake Mills Municipal Water Dept-South?
EPA lists Lake Mills Municipal Water Dept-South as owned by a local government. 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. 8 of the 19 active systems in Winnebago County (42%) are also owned by a local government.
Does Lake Mills Municipal Water Dept-South have drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in April 2001. The violations listed here began between July 1991 and April 2001. By type: 3 monitoring and reporting and 3 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (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 |
|---|---|---|---|---|
| 2001-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2001-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2000-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2000-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1991-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1991-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | 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.
Lake Mills Municipal Water Dept-South: frequently asked questions
Who runs Lake Mills Municipal Water Dept-South?
Lake Mills Municipal Water Dept-South (PWSID IA9545044) is a community water system owned by a local government. It is regulated by the IA state drinking water program.
How many people does Lake Mills Municipal Water Dept-South serve?
Lake Mills Municipal Water Dept-South reports serving 2,158 people through 1,116 service connections in Winnebago County, Iowa.
Where does Lake Mills Municipal Water Dept-South 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 Lake Mills Municipal Water Dept-South have any drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in April 2001. 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 Lake Mills Municipal Water Dept-South'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; 3 are health-based, and the most recent began in April 2001. For current results, consult the system's annual water quality report, EPA ECHO, or the IA state drinking water program.
Where can I find Lake Mills Municipal Water Dept-South's water quality report?
As a community water system, Lake Mills Municipal Water Dept-South 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 Winnebago County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Forest City Water Supply | Winnebago | 4,285 | Community | Groundwater |
| Buffalo Center Muni Water Dept | Winnebago | 857 | Community | Groundwater |
| Thompson Water Works | Winnebago | 499 | Community | Groundwater |
| Three Fingers Campground | Winnebago | 252 | Transient non-community | Groundwater |
| Leland Water Supply | Winnebago | 249 | Community | Groundwater |
| Rake Water Supply | Winnebago | 186 | 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, “Lake Mills Municipal Water Dept-South, PWSID IA9545044, Iowa”, https://aquacensus.com/water-systems/iowa/lake-mills-municipal-water-dept-south-ia9545044 (data as of October 1, 2026).