F0/100
Oswego Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 38,169 residents · Illinois
What's In Oswego's Tap Water?
66
Contaminants Tested
0
Exceed EPA Limits
2
Above EPA Goals
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
strontium | 2638.60 µg/L | — | Above Goal |
Lead (90th percentile) | 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
2
Violations (last 5yr)
0
Unresolved
0
Health-Related
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: September 1, 2024 – September 30, 2024Rule: Stage 1 DBPREnforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2022 – June 9, 2023Enforcement: 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
OSWEGO
Population Served
38,169
Water Source
Groundwater
System ID
IL0930150
Frequently Asked Questions About Oswego Water
Is Oswego tap water safe to drink?
Oswego, Illinois tap water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA maximum contaminant levels and 56 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Oswego's water?
Of the 66 contaminants tested in Oswego's water supply, the most notable include Lead (90th percentile), strontium. No contaminants exceed EPA legal limits. 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Oswego have any water quality violations?
Yes, Oswego has 56 EPA violation(s) on record, with the most recent in 2024. Violation types include MR, Other, MCL. 24 of these are health-based violations, which are the most serious category.
Do I need a water filter in Oswego?
Oswego 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. 2 contaminant(s) exceed these stricter goals.
Where does Oswego's tap water come from?
Oswego's drinking water is sourced from groundwater and supplied by OSWEGO. The system serves approximately 38,169 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Oswego'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. Oswego'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 Oswego's water compare to other cities in Illinois?
Oswego's water quality score of 0/100 earns a grade of F, which is considered failing. 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 Oswego's water quality?
If you have concerns about Oswego'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 (OSWEGO) 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.