Public water system · IA8018040
ActiveDiagonal Water Department
At a glance
Diagonal Water Department (PWSID IA8018040) is an active community water system in Ringgold County, Iowa. It reports serving 338 people through 133 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
338
Service connections
133
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Diagonal Water Department compare with other water systems in Ringgold County?
By EPA's size categories, Diagonal Water Department is a very small system (500 people or fewer). Ringgold County has 3 active public water systems, and Diagonal Water Department is the 2nd-largest of them by population served. Its population served is about 55% below the county average of 756 people per system, and accounts for 15% of the 2,268 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 Diagonal Water Department 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 119 Iowa systems (6.5%) list purchased surface water as their primary source.
Who owns and regulates Diagonal Water Department?
EPA lists Diagonal Water Department 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. 3 of the 3 active systems in Ringgold County (100%) are also owned by a local government.
Does Diagonal Water Department have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025. The violations listed here began between November 2019 and November 2025. By type: 7 monitoring and reporting, 3 monitoring and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Revised Total Coliform Rule (3 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 |
|---|---|---|---|---|
| 2025-11-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2025-11-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2025-06-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2025-03-21 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2024-10-21 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Unaddressed |
| 2024-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2024-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitritecode 1041 | No | Resolved |
| 2024-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitritecode 1041 | No | Resolved |
| 2024-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitritecode 1041 | No | Resolved |
| 2023-04-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2021-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-11-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | 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.
Diagonal Water Department: frequently asked questions
Who runs Diagonal Water Department?
Diagonal Water Department (PWSID IA8018040) is a community water system owned by a local government. It is regulated by the IA state drinking water program.
How many people does Diagonal Water Department serve?
Diagonal Water Department reports serving 338 people through 133 service connections in Ringgold County, Iowa.
Where does Diagonal Water Department get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Diagonal Water Department have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 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 Diagonal Water Department'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, none is health-based, and the most recent began in November 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 Diagonal Water Department's water quality report?
As a community water system, Diagonal Water Department 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 Ringgold County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Mount Ayr Water Treatment Plant | Ringgold | 1,683 | Community | Purchased surface water |
| Kellerton Water Supply | Ringgold | 247 | Community | Purchased surface water |
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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, “Diagonal Water Department, PWSID IA8018040, Iowa”, https://aquacensus.com/water-systems/iowa/diagonal-water-department-ia8018040 (data as of October 1, 2026).