Troy, IL
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2026-2028). 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.
About Troy
Troy serves about 16,962 people through 6,767 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 Madison County, Illinois. EPA system ID: IL1191000; phone on file: 618-667-9924. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2025 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Troy is 2.8 ppb across 13 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2028 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2024 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2023 | 1.5 ppb |
| 2022 | 1.2 ppb |
| 2022 | 1.6 ppb |
| 2021 | 2.3 ppb |
| 2021 | 2.4 ppb |
| 2020 | 2.8 ppb |
| 2020 | 1.5 ppb |
| 2019 | 1.7 ppb |
| 2017 | 1.9 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. Troy's reported as 0 (not detected) sits at the 53rd percentile in Illinois and the 38th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
35 other systems share Madison County; 16 of them have a higher latest lead result than Troy. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Il American-Alton | 46,127 | 3 ppb |
| Il American-Granite City | 33,572 | 6 ppb |
| Collinsville | 30,616 | 0 (not detected) |
| Edwardsville | 26,808 | 0 (not detected) |
| Bethalto | 15,210 | 1.2 ppb |
| Glen Carbon | 12,618 | 0 (not detected) |
| Highland | 10,674 | 0 (not detected) |
| Wood River | 10,464 | 0 (not detected) |
| Maryville | 10,150 | 2 ppb |
| Fosterburg Pwd | 7,940 | 2.8 ppb |
What to do in your house
Look up your address in Troy'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 Troy whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1690 ppb (copper action level 1,300 ppb).
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.