Mundelein, IL
Exceeded the action level in the past
Latest 90th-percentile lead: 4.3 ppb (monitoring period 2026-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest result is under the action level, but this system has gone over 15 ppb before. Lead comes from pipes, not the source water, so a home with a lead service line can still be exposed. Test your own tap.
Mundelein at a glance
Mundelein serves about 31,500 people through 10,876 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Lake County, Illinois. EPA system ID: IL0971150; phone on file: 847-949-3281. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Mundelein's lead record
That is up 4.3 ppb from 0 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Mundelein is 54 ppb across 8 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 4.3 ppb |
| 2025 | 0 (not detected) |
| 2025 | 1.6 ppb |
| 2025 | 7.4 ppb |
| 2025 | 54 ppb over 15 |
| 2023 | 2.3 ppb |
| 2020 | 2 ppb |
| 2017 | 2.7 ppb |
Where this result ranks
Of the 1,744 Illinois systems with a lead result, the median latest reading is 0 ppb; 22 are over 15 ppb right now and 152 have gone over at some point. Mundelein's 4.3 ppb sits at the 85th percentile in Illinois and the 89th nationally (higher means more lead).
Neighbouring systems
103 other systems share Lake County; 24 of them have a higher latest lead result than Mundelein. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Waukegan | 87,149 | 10 ppb |
| Vernon Hills - Lake Co Pw | 33,207 | 0 (not detected) |
| Gurnee | 30,193 | 0.3 ppb |
| Highland Park | 30,176 | 0 (not detected) |
| Round Lake Beach | 27,200 | 0 (not detected) |
| Zion | 24,442 | 11.2 ppb |
| Great Lakes Naval Training Station | 23,000 | 0 (not detected) |
| Grayslake | 21,248 | 11 ppb |
| Libertyville | 20,500 | 5.61 ppb |
| Lake Zurich | 19,759 | 4.67 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Mundelein, IL may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Mundelein whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. What a 90th-percentile result does and does not tell you: how to read a lead result. Why an old exceedance still matters: over the limit before, under it now.