Northernaire Sanitary District, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 2.5 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
Northernaire Sanitary District serves about 315 people through 7 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 Oneida County, Wisconsin. EPA system ID: WI7440812. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
That is down 5.75 ppb from 8.25 ppb in the period ending 2021. The highest 90th-percentile result EPA holds for Northernaire Sanitary District is 8.25 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2.5 ppb |
| 2021 | 8.25 ppb |
| 2018 | 1.95 ppb |
Against other Wisconsin systems
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. Northernaire Sanitary District's 2.5 ppb sits at the 70th percentile in Wisconsin and the 77th nationally (higher means more lead).
Other water systems in Oneida County
7 other systems share Oneida County; 2 of them have a higher latest lead result than Northernaire Sanitary District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Rhinelander Water & Wastewater | 8,234 | 1 ppb |
| Lakeland Sanitary Dist 1 | 2,381 | 2.2 ppb |
| Three Lakes Sanitary District | 500 | 11.2 ppb |
| Mcnaughton Correctional Center | 133 | 0 (not detected) |
| Patricia Lake Manufactured Housing Community | 56 | 1.18 ppb |
| Fishermans Paradise Mhp | 54 | 3.09 ppb |
| Rockwood Estates | 48 | 1.14 ppb |
Next steps for Three Lakes, WI
Test your own tap with a certified lab first-draw sample; Three Lakes, 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 Northernaire Sanitary 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. 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.