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Community Water System · PWS IL0315185

Oasis MHP

Northbrook, Illinois 60062 - drinking water served from groundwater sources to 3,000 people, tracked in EPA SDWIS and UCMR5.

3,000
People served
101
EPA violations
20
Health-based
Untested
UCMR5 result

The verdict

EPA records 101 drinking-water violations at Oasis MHP, 20% of them health-based - above the Illinois per-system average.

101
Total EPA violations on record
20%
Health-based (MCL / treatment failure)
3,000
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Oasis MHP

Oasis MHP is a private-owned community water system that delivers drinking water to 3,000 residents in Northbrook, Illinois (Cook County) through 599 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 101 total violations for this system , of which 20 (20%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 62 monitoring and reporting violations are on file. The most recent violation on record dates to 2021.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 20 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%).

Oasis MHP's 101 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
3,000
Total Violations
101
Health-Based Violations
20
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
599
County
Cook
School/Daycare
No
MCL Violations
20
Monitoring Violations
62
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MCL 20 1997
Coliform (TCR) MR 14 1997
Chlorine MR 4 2011
TTHM MR 4 2021
Total Haloacetic Acids (HAA5) MR 4 2021
Antimony, Total MR 4 2020
Beryllium, Total MR 4 2020
Nickel MR 4 2020
Selenium MR 4 2020
Barium MR 4 2020
Mercury MR 4 2020
Total Polychlorinated Biphenyls (PCB) MR 4 2020
Cadmium MR 4 2020
Thallium, Total MR 4 2020
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 Oasis MHP.

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 IL0315185 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 Oasis MHP 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
2021 TTHM MR 4 SDWIS / IL0315185 / 2950
2021 Total Haloacetic Acids (HAA5) MR 4 SDWIS / IL0315185 / 2456
2020 Antimony, Total MR 4 SDWIS / IL0315185 / 1074
2020 Beryllium, Total MR 4 SDWIS / IL0315185 / 1075
2020 Nickel MR 4 SDWIS / IL0315185 / 1036
2020 Selenium MR 4 SDWIS / IL0315185 / 1045
2020 Barium MR 4 SDWIS / IL0315185 / 1010
2020 Mercury MR 4 SDWIS / IL0315185 / 1035
2020 Total Polychlorinated Biphenyls (PCB) MR 4 SDWIS / IL0315185 / 2383
2020 Cadmium MR 4 SDWIS / IL0315185 / 1015
2020 Thallium, Total MR 4 SDWIS / IL0315185 / 1085
2012 Consumer Confidence Rule Other 2 SDWIS / IL0315185 / 7000
2011 Chlorine MR 4 SDWIS / IL0315185 / 0999
1997 Coliform (TCR) MCL 20 SDWIS / IL0315185 / 3100
1997 Coliform (TCR) MR 14 SDWIS / IL0315185 / 3100

How Oasis MHP Compares

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

Metric Oasis MHP Illinois avg Federal benchmark
Total violations 101 69.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 20 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 3,000 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 Oasis MHP water safe to drink? ▼
Oasis MHP (PWS ID: IL0315185) has 101 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 3,000 people using Groundwater sources.
How many people does Oasis MHP serve? ▼
Oasis MHP serves 3,000 people in Northbrook, Illinois. It is a Private-owned system using Groundwater water sources with 599 service connections.
What type of violations does Oasis MHP have? ▼
Oasis MHP has 101 total violations: 20 health-based violations (MCL exceedances or treatment failures), 62 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Oasis MHP water? ▼
No PFAS testing data is available for Oasis MHP under the EPA's UCMR5 monitoring program.
What water source does Oasis MHP use? ▼
Oasis MHP 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.