Leyden Twsp Water District, IL
Exceeded the action level in the past
Latest 90th-percentile lead: 8.33 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.
Leyden Twsp Water District at a glance
Leyden Twsp Water District serves about 10,000 people through 2,973 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 Cook County, Illinois. EPA system ID: IL0315880; phone on file: 847-455-8616. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
That is up 8.33 ppb from 0 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Leyden Twsp Water District is 16.6 ppb across 8 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 8.33 ppb |
| 2025 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2025 | 12.7 ppb over 10 |
| 2025 | 16.6 ppb over 15 |
| 2023 | 6.08 ppb |
| 2020 | 0 (not detected) |
| 2017 | 7.65 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. Leyden Twsp Water District's 8.33 ppb sits at the 94th percentile in Illinois and the 96th nationally (higher means more lead).
Other water systems in Cook County
154 other systems share Cook County; 24 of them have a higher latest lead result than Leyden Twsp Water District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Chicago | 2,721,308 | 6.4 ppb |
| Cicero | 83,000 | 5 ppb |
| Schaumburg | 75,750 | 0.87 ppb |
| Evanston | 74,486 | 6.5 ppb |
| Arlington Heights | 73,320 | 7.6 ppb |
| Palatine | 70,875 | 8.9 ppb |
| Skokie | 66,422 | 9.77 ppb |
| Des Plaines | 60,675 | 5.7 ppb |
| Oak Lawn | 58,362 | 9.3 ppb |
| Orland Park | 58,020 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Franklin Park, 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 Leyden Twsp Water District 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.