Mendota Mental Health Inst, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 7 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.
Mendota Mental Health Inst at a glance
Mendota Mental Health Inst serves about 2,787 people through 1,032 service connections, which makes it a small system under EPA's size classes. It is owned by the state and draws groundwater, in Dane County, Wisconsin. EPA system ID: WI1130235. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
That is up 5.7 ppb from 1.3 ppb in the period ending 2024. The highest 90th-percentile result EPA holds for Mendota Mental Health Inst is 7.7 ppb across 10 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 7 ppb |
| 2024 | 1.3 ppb |
| 2024 | 3.2 ppb |
| 2020 | 5.2 ppb |
| 2019 | 7.7 ppb |
| 2019 | 5.8 ppb |
| 2018 | 4.7 ppb |
| 2018 | 4 ppb |
| 2017 | 2 ppb |
| 2016 | 4 ppb |
Where this result ranks
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. Mendota Mental Health Inst's 7 ppb sits at the 94th percentile in Wisconsin and the 95th nationally (higher means more lead).
Nearby utilities
42 other systems share Dane County; 1 of them has a higher latest lead result than Mendota Mental Health Inst. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Madison Water Utility | 272,000 | 1.8 ppb |
| Sun Prairie Utilities | 39,300 | 2.8 ppb |
| Fitchburg Utility Dist 1 | 29,900 | 2.3 ppb |
| Middleton Waterworks | 23,868 | 4 ppb |
| Waunakee Waterworks | 14,879 | 1.7 ppb |
| Verona Waterworks | 14,030 | 2.86 ppb |
| Stoughton Waterworks | 13,078 | 4.2 ppb |
| Oregon Waterworks | 11,200 | 4.97 ppb |
| Deforest Waterworks | 10,500 | 5.95 ppb |
| Mcfarland Waterworks | 9,676 | 2.1 ppb |
Next steps for Madison, WI
Test your own tap with a certified lab first-draw sample; Madison, 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 Mendota Mental Health Inst whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1600 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. What a 90th-percentile result does and does not tell you: how to read a lead result. Systems that went over once often dip back under; here is what that means.