Yorkville, IL
Lead detected, under the action levels
Latest 90th-percentile lead: 0.75 ppb (monitoring period 2025-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
About Yorkville
Yorkville serves about 23,000 people through 8,695 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 groundwater, in Kendall County, Illinois. EPA system ID: IL0930250; phone on file: 630-553-4350. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Every lead result on file
Against the period ending 2025 (1.45 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Yorkville is 9.46 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0.75 ppb |
| 2025 | 1.45 ppb |
| 2023 | 1.2 ppb |
| 2020 | 7.01 ppb |
| 2017 | 9.46 ppb |
How Yorkville compares
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. Yorkville's 0.75 ppb sits at the 58th percentile in Illinois and the 47th nationally (higher means more lead).
Neighbouring systems
8 other systems share Kendall County; 5 of them have a higher latest lead result than Yorkville. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Oswego | 38,169 | 0 (not detected) |
| Plano | 12,600 | 2.3 ppb |
| Il American-Valley Marina | 1,102 | 4 ppb |
| Newark | 986 | 0 (not detected) |
| Fox Lawn Homeowners Water Association | 167 | 0 (not detected) |
| Il American-Hollis | 107 | 1 ppb |
| Storybook Highlands | 100 | 2.62 ppb |
| Morgan Creek | 66 | 6.89 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Yorkville, 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 Yorkville 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. Systems that went over once often dip back under; here is what that means.