St. Thomas More School-Main System
PWSID: CT0861251
This system has no unresolved violations. The most recent violation on record was 2025-01-01.
This system has more violations on record than 86% of water systems in Connecticut.
Violation trend: 2.0 per year over the last 5 years, up from 1.0 per year in the previous 5.
System Details
| Population Served | 270 |
| Service Connections | 27 |
| Water Source | Groundwater |
| System Type | Community Water System |
| Owner | Private |
| Status | Active |
| City | Oakdale |
| EPA ZIP on File | 06370 |
| Note | School or Daycare |
Areas Served
- Montville, New London County
Lead & Copper Testing
| Contaminant | Level | EPA Action Level | Status |
|---|---|---|---|
| Lead (90th percentile) | 0.0250 mg/L | 0.015 mg/L | Exceeds Action Level |
| Lead (90th percentile) | 0.0033 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0025 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0023 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0017 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0015 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0015 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0000 mg/L | 0.015 mg/L | Below Action Level |
Violation History (39 total)
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 1044 | MR | 2025-01-01 | Acknowledged | |
| 1044 | MR | 2025-01-01 | Acknowledged | |
| 7500 | Other | 2024-05-26 | Returned to Compliance | |
| 7500 | Other | 2024-05-26 | Returned to Compliance | |
| 5000 | MR | 2023-01-01 | Returned to Compliance | |
| 5000 | MR | 2023-01-01 | Returned to Compliance | |
| 5000 | MR | 2023-01-01 | Returned to Compliance | |
| 5000 | MR | 2023-01-01 | Returned to Compliance | |
| 5000 | MR | 2023-01-01 | Returned to Compliance | |
| 5000 | MR | 2021-09-29 | Returned to Compliance | |
| 2950 | MR | 2019-08-01 | Major | Returned to Compliance |
| 2456 | MR | 2019-08-01 | Major | Returned to Compliance |
| 7500 | Other | 2017-06-28 | Returned to Compliance | |
| 5000 | MR | 2017-04-01 | Returned to Compliance | |
| 7000 | Other | 2016-07-01 | Returned to Compliance | |
| 5000 | MR | 2016-01-01 | Returned to Compliance | |
| 5000 | MR | 2015-09-29 | Returned to Compliance | |
| 5000 | MR | 2015-07-01 | Returned to Compliance | |
| 5000 | MR | 2015-04-01 | Returned to Compliance | |
| 5000 | MR | 2014-09-29 | Returned to Compliance | |
| 7000 | Other | 2014-08-10 | Returned to Compliance | |
| 7000 | Other | 2014-07-01 | Returned to Compliance | |
| 5000 | MR | 2014-04-01 | Returned to Compliance | |
| 5000 | TT | 2014-03-02 | Yes | Returned to Compliance |
| 5000 | MR | 2014-01-01 | Returned to Compliance | |
| 5000 | TT | 2013-08-30 | Yes | Returned to Compliance |
| 5000 | MR | 2013-07-01 | Returned to Compliance | |
| 5000 | MR | 2013-01-01 | Returned to Compliance | |
| 5000 | MR | 2012-03-31 | Returned to Compliance | |
| 5000 | MR | 2011-09-29 | Returned to Compliance | |
| 7000 | Other | 2011-07-01 | Returned to Compliance | |
| 5000 | MR | 2010-09-29 | Returned to Compliance | |
| 7000 | Other | 2009-07-01 | Returned to Compliance | |
| 7000 | Other | 2008-10-01 | Returned to Compliance | |
| 7000 | Other | 2008-07-01 | Returned to Compliance | |
| 7000 | Other | 2007-07-01 | Returned to Compliance | |
| 7000 | Other | 2006-07-01 | Returned to Compliance | |
| 5000 | MR | 2001-10-01 | Returned to Compliance | |
| 5000 | MR | 1994-07-01 | Returned to Compliance |
Understanding This Water System's Record
St. Thomas More School-Main System is a community water system water system that draws from groundwater sources and serves a population of 270 in Oakdale, Connecticut. This page shows its complete compliance history as reported to the EPA's Safe Drinking Water Information System (SDWIS), the federal database that tracks every public water system in the United States.
What Do These Violations Mean?
Health-based violations mean the system exceeded an EPA maximum contaminant level (MCL) or failed to provide required treatment. These indicate potential health risks from contaminants like lead, arsenic, bacteria, nitrates, or disinfection byproducts. Non-health-based violations involve monitoring, reporting, or procedural requirements — the system missed a testing deadline or failed to notify customers, but contaminant levels were not necessarily unsafe.
What Should You Do?
Your water utility is required to publish an annual Consumer Confidence Report (CCR) that details test results and any violations. If your system has active health-based violations, consider a certified water filter rated for the specific contaminants involved. The contaminant guides on this site explain health risks and filter options for common pollutants. For the most current results, contact your water utility directly — EPA data can lag weeks or months behind real-time testing.