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Community Water System · PWS IL0970250

Grayslake

Grayslake, Illinois 60030 - drinking water served from surface water sources to 21,248 people, tracked in EPA SDWIS and UCMR5.

21,248
People served
33
EPA violations
13
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 33 drinking-water violations at Grayslake, 39% of them health-based - below the Illinois per-system average.

33
Total EPA violations on record
39%
Health-based (MCL / treatment failure)
21,248
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Grayslake

Grayslake is a local-owned community water system that delivers drinking water to 21,248 residents in Grayslake, Illinois (Lake County) through 7,024 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 33 total violations for this system , of which 13 (39%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 8 monitoring and reporting violations are on file. The most recent violation on record dates to 2006.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 9 violations (MCL, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

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%).

Grayslake's 33 violations sit below 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
21,248
Total Violations
33
Health-Based Violations
13
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
7,024
County
Lake
School/Daycare
No
MCL Violations
9
Monitoring Violations
8
Treatment Tech Violations
4

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MCL 9 2000
Lead and Copper Rule TT 4 1994
Lead and Copper Rule MR 4 2006
Coliform (TCR) MR 3 1995
Gross Alpha, Excl. Radon and U MR 1 1977

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.

Contaminant Date Result MRL Status
6:2 FTS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 9/25/2023 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 9/25/2023 <7.00 ppt 7.00 ppt Not Detected
PFTA 9/25/2023 <8.00 ppt 8.00 ppt Not Detected
PFHpS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 9/25/2023 <20.00 ppt 20.00 ppt Not Detected
PFMBA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFMPA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
8:2 FTS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFEESA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
ADONA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/25/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFUnA 9/25/2023 <2.00 ppt 2.00 ppt Not Detected
PFHxA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFDA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFOA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFNA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFHxS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
4:2 FTS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFBS 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFMPA 6/12/2023 <4.00 ppt 4.00 ppt Not Detected
8:2 FTS 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFEESA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFBA 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
NFDHA 6/12/2023 <20.00 ppt 20.00 ppt Not Detected
PFTA 6/12/2023 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 6/12/2023 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 6/12/2023 <6.00 ppt 6.00 ppt Not Detected
6:2 FTS 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFDA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
9Cl-PF3ONS 6/12/2023 <2.00 ppt 2.00 ppt Not Detected
11Cl-PF3OUdS 6/12/2023 <5.00 ppt 5.00 ppt Not Detected
PFUnA 6/12/2023 <2.00 ppt 2.00 ppt Not Detected
PFHpA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 6/12/2023 <3.00 ppt 3.00 ppt Not Detected

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 Grayslake.

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 IL0970250 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 Grayslake 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
2006 Lead and Copper Rule MR 4 SDWIS / IL0970250 / 5000
2000 Coliform (TCR) MCL 9 SDWIS / IL0970250 / 3100
1995 Coliform (TCR) MR 3 SDWIS / IL0970250 / 3100
1994 Lead and Copper Rule TT 4 SDWIS / IL0970250 / 5000
1977 Gross Alpha, Excl. Radon and U MR 1 SDWIS / IL0970250 / 4000

How Grayslake Compares

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

Metric Grayslake Illinois avg Federal benchmark
Total violations 33 69.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 13 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 21,248 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 Grayslake water safe to drink? ▼
Grayslake (PWS ID: IL0970250) has 33 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 21,248 people using Surface Water sources.
How many people does Grayslake serve? ▼
Grayslake serves 21,248 people in Grayslake, Illinois. It is a Local-owned system using Surface Water water sources with 7,024 service connections.
What type of violations does Grayslake have? ▼
Grayslake has 33 total violations: 13 health-based violations (MCL exceedances or treatment failures), 8 monitoring/reporting violations, and 4 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Grayslake water? ▼
No. Grayslake was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Grayslake use? ▼
Grayslake uses Surface Water 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. PFAS data from EPA UCMR5 monitoring program (2023-2025). 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.