Little Swan Lake Sd, IL
Exceeded the action level in the past
Latest 90th-percentile lead: reported as 0 (not detected) (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.
About Little Swan Lake Sd
Little Swan Lake Sd serves about 438 people through 175 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Warren County, Illinois. EPA system ID: IL1875050; phone on file: 309-333-3762. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
That is down 55 ppb from 55 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Little Swan Lake Sd is 55 ppb across 5 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2025 | 55 ppb over 15 |
| 2022 | 15 ppb over 10 |
| 2019 | 3.6 ppb |
| 2016 | 0 (not detected) |
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. Little Swan Lake Sd's reported as 0 (not detected) sits at the 18th percentile in Illinois and the 21st nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
5 other systems share Warren County; 3 of them have a higher latest lead result than Little Swan Lake Sd. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Monmouth | 8,902 | 2.9 ppb |
| Roseville | 915 | 0 (not detected) |
| Alexis | 836 | 75.8 ppb |
| Kirkwood | 714 | 1.5 ppb |
| Little York | 304 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Monmouth, 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 Little Swan Lake Sd 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. More in what a past exceedance means today.