Aqua Illinois-Nunda, IL
Lead detected, under the action levels
Latest 90th-percentile lead: 1.9 ppb (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. 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.
Aqua Illinois-Nunda at a glance
Aqua Illinois-Nunda serves about 485 people through 194 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Mchenry County, Illinois. EPA system ID: IL1115600; phone on file: 224-602-6779. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
That is down 2.6 ppb from 4.5 ppb in the period ending 2023. The highest 90th-percentile result EPA holds for Aqua Illinois-Nunda is 9.7 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 1.9 ppb |
| 2023 | 4.5 ppb |
| 2020 | 3.4 ppb |
| 2017 | 9.7 ppb |
Against other Illinois systems
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. Aqua Illinois-Nunda's 1.9 ppb sits at the 71st percentile in Illinois and the 68th nationally (higher means more lead).
Other water systems in Mchenry County
31 other systems share Mchenry County; 13 of them have a higher latest lead result than Aqua Illinois-Nunda. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Crystal Lake | 40,661 | 6.8 ppb |
| Algonquin | 30,700 | 1.96 ppb |
| Lake In The Hills | 28,661 | 0 (not detected) |
| Huntley | 28,495 | 1.1 ppb |
| Woodstock | 25,630 | 1.5 ppb |
| Mchenry | 22,335 | 6.7 ppb |
| Cary | 17,826 | 1.7 ppb |
| Harvard | 9,469 | 7.1 ppb |
| Il American-Whispering Hills | 8,300 | 0 (not detected) |
| Marengo | 7,572 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Glenview, 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 Aqua Illinois-Nunda 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. Why sampled homes are the worst-case ones is in the guide to reading the number. Size matters more than most people expect: small vs large water systems.