Winfield, IL
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2024-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Winfield serves about 9,835 people through 3,830 service connections, which makes it a medium-sized system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Dupage County, Illinois. EPA system ID: IL0431150; phone on file: 630-933-2125. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
Against the period ending 2023 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Winfield is 2.39 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2020 | 2.39 ppb |
| 2017 | 0 (not detected) |
How Winfield 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. Winfield's reported as 0 (not detected) sits at the 51st percentile in Illinois and the 37th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in Dupage County
47 other systems share Dupage County; 26 of them have a higher latest lead result than Winfield. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Naperville | 156,406 | 6.1 ppb |
| Wheaton | 53,970 | 2.32 ppb |
| Downers Grove | 49,425 | 4.98 ppb |
| Elmhurst | 45,000 | 5.52 ppb |
| Lombard | 44,476 | 10.6 ppb |
| Carol Stream | 39,854 | 1.05 ppb |
| Addison | 38,017 | 2 ppb |
| Woodridge | 33,566 | 0 (not detected) |
| Glendale Heights | 33,176 | 0 (not detected) |
| Glen Ellyn | 28,500 | 1.87 ppb |
What to do in your house
Look up your address in Winfield's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Winfield 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. The lead result guide covers how utilities pick the homes they sample. Small systems behave differently: why small systems go over more often.