Markham
PWSID: IL0311770
This system has unresolved violations related to monitoring, reporting, or procedural requirements, but none involve contaminant levels exceeding EPA health limits.
This system has more violations on record than 85% of water systems in Illinois.
Violation trend: 3.2 per year over the last 5 years, up from 0.2 per year in the previous 5.
System Details
| Population Served | 12,500 |
| Service Connections | 4,138 |
| Water Source | Surface Water Purchased |
| System Type | Community Water System |
| Owner | Local Government |
| Status | Active |
| City | Markham |
| EPA ZIP on File | 60428 |
Areas Served
- Markham, Cook County
Lead & Copper Testing
| Contaminant | Level | EPA Action Level | Status |
|---|---|---|---|
| Lead (90th percentile) | 0.0030 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0026 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0024 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0021 mg/L | 0.015 mg/L | Below Action Level |
2 Active Violations
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 5200 | RPT | 2025-07-02 | Open | |
| 7000 | Other | 2025-07-01 | Open |
Violation History (20 total)
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 2950 | MR | 2025-07-01 | Major | Acknowledged |
| 7000 | Other | 2023-07-01 | Returned to Compliance | |
| 7000 | Other | 2023-07-01 | Returned to Compliance | |
| 7500 | Other | 2023-06-15 | Returned to Compliance | |
| 7500 | Other | 2023-06-15 | Returned to Compliance | |
| 7500 | Other | 2023-06-15 | Returned to Compliance | |
| 7500 | Other | 2023-06-15 | Returned to Compliance | |
| 8000 | MON | 2022-05-01 | Returned to Compliance | |
| 8000 | MON | 2022-05-01 | Returned to Compliance | |
| 8000 | MON | 2022-05-01 | Returned to Compliance | |
| 0999 | MR | 2022-04-01 | Major | Returned to Compliance |
| 0999 | MR | 2022-04-01 | Major | Returned to Compliance |
| 0999 | MR | 2022-04-01 | Major | Returned to Compliance |
| 0999 | MR | 2022-04-01 | Major | Returned to Compliance |
| 5000 | MR | 2020-12-30 | Returned to Compliance | |
| 7000 | Other | 2011-07-01 | Returned to Compliance | |
| 5000 | MR | 1996-10-01 | Returned to Compliance | |
| 5000 | MR | 1994-10-01 | Returned to Compliance |
Understanding This Water System's Record
Markham is a community water system water system that draws from surface water purchased sources and serves a population of 12,500 in Markham, Illinois. 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.