D28/100
Markham Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 12,500 residents · Illinois
What's In Markham's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
1
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
8
Violations (last 5yr)
3
Unresolved
0
Health-Related
TIER 3Unresolved
Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 2, 2025Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 3Unresolved
Surface water treatment technique failure
TIER 3Unresolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2023 – July 11, 2023Enforcement: Resolving — corrective action underway
TIER 3Resolved
Disinfection byproduct treatment technique failure
When: June 15, 2023 – June 20, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Disinfection byproduct treatment technique failure
When: June 15, 2023 – June 20, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: May 1, 2022 – May 31, 2022Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2022 – June 23, 2022Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
MARKHAM
Population Served
12,500
Water Source
Purchased Surface Water
System ID
IL0311770
Frequently Asked Questions About Markham Water
Is Markham tap water safe to drink?
Markham, Illinois tap water receives a grade of D (28/100), which is considered poor. 0 contaminant(s) exceed EPA maximum contaminant levels and 41 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Markham's water?
Of the 69 contaminants tested in Markham's water supply, the most notable include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Markham have any water quality violations?
Yes, Markham has 41 EPA violation(s) on record, with the most recent in 2025. Violation types include RPT, Other, MR. 7 of these are health-based violations, which are the most serious category.
Do I need a water filter in Markham?
Markham water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.
Where does Markham's tap water come from?
Markham's drinking water is sourced from purchased surface water and supplied by MARKHAM. The system serves approximately 12,500 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Markham's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Markham's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Markham's water compare to other cities in Illinois?
Markham's water quality score of 28/100 earns a grade of D, which is considered poor. This is a concerning score that suggests significant water quality issues. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Markham's water quality?
If you have concerns about Markham's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (MARKHAM) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.