A80/100
Mount Prospect Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 41,000 residents · Illinois
What's In Mount Prospect'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) | 0.004 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
7
Violations (last 5yr)
2
Unresolved
0
Health-Related
TIER 3Unresolved
Surface water treatment technique failure
TIER 3Unresolved
Surface water treatment technique failure
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: December 1, 2024 – December 31, 2024Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Revised Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Revised Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Revised Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Revised Total Coliform RuleEnforcement: 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
MOUNT PROSPECT
Population Served
41,000
Water Source
Purchased Surface Water
System ID
IL0311980
Frequently Asked Questions About Mount Prospect Water
Is Mount Prospect tap water safe to drink?
Mount Prospect, Illinois tap water receives a grade of A (80/100), which is considered excellent. Out of 69 contaminants tested, none exceed EPA maximum contaminant levels (MCLs) and 1 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Mount Prospect's water?
Of the 69 contaminants tested in Mount Prospect'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 Mount Prospect have any water quality violations?
Yes, Mount Prospect has 13 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MON, MR. 1 of these are health-based violations, which are the most serious category.
Do I need a water filter in Mount Prospect?
Mount Prospect 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 Mount Prospect's tap water come from?
Mount Prospect's drinking water is sourced from purchased surface water and supplied by MOUNT PROSPECT. The system serves approximately 41,000 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Mount Prospect'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. Mount Prospect'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 Mount Prospect's water compare to other cities in Illinois?
Mount Prospect's water quality score of 80/100 earns a grade of A, which is considered excellent. This places Mount Prospect among the better-performing water systems in Illinois. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Mount Prospect's water quality?
If you have concerns about Mount Prospect'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 (MOUNT PROSPECT) 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.