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Community Water System · PWS IL0975736

Elm Oak Mutual Water System

Lake Forest, Illinois 60046 - drinking water served from groundwater sources to 50 people, tracked in EPA SDWIS and UCMR5.

50
People served
571
EPA violations
442
Health-based
Untested
UCMR5 result

The verdict

EPA records 571 drinking-water violations at Elm Oak Mutual Water System, 77% of them health-based - above the Illinois per-system average.

571
Total EPA violations on record
77%
Health-based (MCL / treatment failure)
50
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Elm Oak Mutual Water System

Elm Oak Mutual Water System is a private-owned community water system that delivers drinking water to 50 residents in Lake Forest, Illinois (Lake County) through 20 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 571 total violations for this system , of which 442 (77%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 70 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Combined Radium (-226 and -228), recorded in 391 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across Illinois, EPA tracks 5,117 public water systems serving 12,576,876 people, with 355,322 cumulative violations and 52,932 health-based violations on record. About 81% of systems in the state carry at least one violation, and state-wide the average per system is 69.4 violations. Statewide, 199 of 487 UCMR5-tested systems have reported PFAS detections (40.9%).

Elm Oak Mutual Water System's 571 violations sit above the Illinois average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
50
Total Violations
571
Health-Based Violations
442
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
20
County
Lake
School/Daycare
No
MCL Violations
442
Monitoring Violations
70
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Combined Radium (-226 and -228) MCL 391 2019
Gross Alpha, Excl. Radon and U MCL 51 2009
Combined Radium (-226 and -228) MR 29 2020
Coliform (TCR) MR 23 1992
Public Notice Other 16 2024
Gross Alpha, Excl. Radon and U MR 5 1992
Combined Uranium MR 5 2019
Chlorine MR 4 2018
Revised Total Coliform Rule MON 4 2018
Consumer Confidence Rule Other 2 2012

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Elm Oak Mutual Water System.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID IL0975736 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Illinois Drinking Water Authority

Illinois EPA, Bureau of Water is the primacy agency that licenses and inspects Elm Oak Mutual Water System under EPA-delegated authority.

Open IL regulator portal

Source: Illinois EPA, Bureau of Water

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2024 Public Notice Other 16 SDWIS / IL0975736 / 7500
2020 Combined Radium (-226 and -228) MR 29 SDWIS / IL0975736 / 4010
2019 Combined Radium (-226 and -228) MCL 391 SDWIS / IL0975736 / 4010
2019 Combined Uranium MR 5 SDWIS / IL0975736 / 4006
2018 Chlorine MR 4 SDWIS / IL0975736 / 0999
2018 Revised Total Coliform Rule MON 4 SDWIS / IL0975736 / 8000
2012 Consumer Confidence Rule Other 2 SDWIS / IL0975736 / 7000
2009 Gross Alpha, Excl. Radon and U MCL 51 SDWIS / IL0975736 / 4000
1992 Coliform (TCR) MR 23 SDWIS / IL0975736 / 3100
1992 Gross Alpha, Excl. Radon and U MR 5 SDWIS / IL0975736 / 4000

How Elm Oak Mutual Water System Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Elm Oak Mutual Water System Illinois avg Federal benchmark
Total violations 571 69.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 442 10.3 Indicates a contaminant exceeded a federal MCL
PFAS detection None 40.9% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 50 2,458 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 5,117 regulated public water systems in Illinois.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Elm Oak Mutual Water System water safe to drink? ▼
Elm Oak Mutual Water System (PWS ID: IL0975736) has 571 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 50 people using Groundwater sources.
How many people does Elm Oak Mutual Water System serve? ▼
Elm Oak Mutual Water System serves 50 people in Lake Forest, Illinois. It is a Private-owned system using Groundwater water sources with 20 service connections.
What type of violations does Elm Oak Mutual Water System have? ▼
Elm Oak Mutual Water System has 571 total violations: 442 health-based violations (MCL exceedances or treatment failures), 70 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Elm Oak Mutual Water System water? ▼
No PFAS testing data is available for Elm Oak Mutual Water System under the EPA's UCMR5 monitoring program.
What water source does Elm Oak Mutual Water System use? ▼
Elm Oak Mutual Water System uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.