Public water system · IL3117762
ActiveSt Marks Day School
At a glance
St Marks Day School (PWSID IL3117762) is an active non-transient non-community water system in Lake County, Illinois. It reports serving 60 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in March 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
60
Service connections
1
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does St Marks Day School compare with other water systems in Lake County?
By EPA's size categories, St Marks Day School is a very small system (500 people or fewer). Lake County has 266 active public water systems. Its population served is well below the county average of 2,442 people per system, and accounts for less than 0.1% of the 649,474 people reported by systems filed under the county. Across Illinois, the 3,872 active systems average 3,204 people each. Nationally, the average active non-transient non-community water system reports serving 430 people, so St Marks Day School is well below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. Illinois has 396 active non-transient non-community water systems, 10% 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 St Marks Day School?
EPA lists St Marks Day School as privately owned. 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. 193 of the 266 active systems in Lake County (73%) are also privately owned.
Does St Marks Day School have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in March 2023. The violations listed here began between January 1999 and March 2023. By type: 12 monitoring and reporting. The contaminant or rule involved most often is Lead and Copper Rule (4 of them). EPA lists 11 as resolved and 1 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 |
|---|---|---|---|---|
| 2023-03-12 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2014-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2012-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2009-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Oxamylcode 2036 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Simazinecode 2037 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Lindane (gamma-BHC)code 2010 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Polychlorinated biphenyls (PCBs), totalcode 2383 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Glyphosatecode 2034 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylene dibromide (EDB)code 2946 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlordanecode 2959 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Pentachlorophenolcode 2326 | 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.
St Marks Day School: frequently asked questions
Who runs St Marks Day School?
St Marks Day School (PWSID IL3117762) is a non-transient non-community water system privately owned. It is regulated by the IL state drinking water program.
How many people does St Marks Day School serve?
St Marks Day School reports serving 60 people through 1 service connection in Lake County, Illinois.
Where does St Marks Day School 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 St Marks Day School 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 March 2023. 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 St Marks Day School'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 March 2023. For current results, consult EPA ECHO, or the IL state drinking water program.
Where can I find St Marks Day School's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. St Marks Day School is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Lake County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Waukegan | Lake | 87,149 | Community | Surface water |
| Vernon Hills - Lake Co Pw | Lake | 33,207 | Community | Purchased surface water |
| Mundelein | Lake | 31,500 | Community | Purchased surface water |
| Gurnee | Lake | 30,193 | Community | Purchased surface water |
| Highland Park | Lake | 30,176 | Community | Surface water |
| Round Lake Beach | Lake | 27,200 | Community | Purchased surface water |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “St Marks Day School, PWSID IL3117762, Illinois”, https://aquacensus.com/water-systems/illinois/st-marks-day-school-il3117762 (data as of October 1, 2026).