Public water system · IL0370100
ActiveDekalb
At a glance
Dekalb (PWSID IL0370100) is an active community water system in DeKalb County, Illinois. It reports serving 40,290 people through 10,815 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
40,290
Service connections
10,815
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Dekalb compare with other water systems in DeKalb County?
By EPA's size categories, Dekalb is a large system (10,001 to 100,000 people). DeKalb County has 43 active public water systems, and Dekalb is the largest of them by population served. Its population served is about 18 times the county average of 2,220 people per system, and accounts for 42% of the 95,450 people reported by systems filed under the county. Across Illinois, the 3,872 active systems average 3,204 people each. Nationally, the average active community water system reports serving 6,703 people, so Dekalb is about 6 times 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. Illinois has 1,773 active community water systems, 46% of the state's 3,872 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,808 Illinois systems (73%) list groundwater as their primary source.
Who owns and regulates Dekalb?
EPA lists Dekalb as owned by a local government. The IL state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 13 of the 43 active systems in DeKalb County (30%) are also owned by a local government.
Does Dekalb have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in July 2025. The violations listed here began between February 1992 and July 2025. By type: 5 monitoring and reporting, 5 contaminant level above the legal limit, 1 public notice, recordkeeping or other and 1 monitoring. The contaminant or rule involved most often is Combined Radium (-226 and -228) (5 of them). EPA lists 9 as resolved and 3 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 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Resolved |
| 2018-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2011-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Resolved |
| 1999-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1998-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 1995-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 1994-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 1992-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1992-04-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1992-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
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.
Dekalb: frequently asked questions
Who runs Dekalb?
Dekalb (PWSID IL0370100) is a community water system owned by a local government. It is regulated by the IL state drinking water program.
How many people does Dekalb serve?
Dekalb reports serving 40,290 people through 10,815 service connections in DeKalb County, Illinois.
Where does Dekalb 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 Dekalb have any drinking water violations?
Of the 12 most recent violations in EPA's records, 5 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 Dekalb'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, 5 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 IL state drinking water program.
Where can I find Dekalb's water quality report?
As a community water system, Dekalb 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 DeKalb County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Sycamore | DeKalb | 18,500 | Community | Groundwater |
| Sandwich | DeKalb | 7,156 | Community | Groundwater |
| Northern Illinois University-Dekalb | DeKalb | 6,500 | Community | Purchased groundwater |
| Genoa | DeKalb | 5,298 | Community | Groundwater |
| Cortland | DeKalb | 4,398 | Community | Groundwater |
| Hinckley | DeKalb | 2,006 | 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, “Dekalb, PWSID IL0370100, Illinois”, https://aquacensus.com/water-systems/illinois/dekalb-il0370100 (data as of October 1, 2026).