Hillsboro Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 3.2 ppb (monitoring period 2025-2025). 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.
Who runs the water here
Hillsboro Waterworks serves about 1,325 people through 661 service connections, which makes it a small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Vernon County, Wisconsin. EPA system ID: WI6630257. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is down 2.1 ppb from 5.3 ppb in the period ending 2023. The highest 90th-percentile result EPA holds for Hillsboro Waterworks is 7 ppb across 11 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 3.2 ppb |
| 2023 | 5.3 ppb |
| 2023 | 5.1 ppb |
| 2021 | 3.9 ppb |
| 2021 | 5.4 ppb |
| 2020 | 5 ppb |
| 2020 | 7 ppb |
| 2019 | 3.8 ppb |
| 2019 | 4.2 ppb |
| 2017 | 4 ppb |
| 2016 | 2.2 ppb |
How Hillsboro Waterworks compares
Of the 947 Wisconsin systems with a lead result, the median latest reading is 1.33 ppb; 6 are over 15 ppb right now and 71 have gone over at some point. Hillsboro Waterworks's 3.2 ppb sits at the 77th percentile in Wisconsin and the 84th nationally (higher means more lead).
Neighbouring systems
13 other systems share Vernon County; 2 of them have a higher latest lead result than Hillsboro Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Viroqua Waterworks | 4,362 | 4.42 ppb |
| Westby Waterworks | 2,400 | 1.46 ppb |
| Stoddard Waterworks | 793 | 0 (not detected) |
| Coon Valley Waterworks | 765 | 0 (not detected) |
| La Farge Waterworks | 712 | 0 (not detected) |
| Viola Waterworks | 667 | 1.22 ppb |
| Ontario Waterworks | 554 | 1.27 ppb |
| Readstown Waterworks | 395 | 1.46 ppb |
| Chaseburg Waterworks Village Of | 306 | 2.76 ppb |
| Genoa Waterworks | 264 | 7.83 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Hillsboro, WI 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 Hillsboro Waterworks whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1450 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. The action level is dropping - the 10 ppb rule from 2027.