Knollcrest, WI
Above the new 10 ppb level coming in 2027
Latest 90th-percentile lead: 13.64 ppb (monitoring period 2023-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Under the current 15 ppb rule this is not an exceedance, but it is above the 10 ppb action level that takes over in Nov 2027. Test your own tap; filter if your result shows lead.
About Knollcrest
Knollcrest serves about 66 people through 52 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Waukesha County, Wisconsin. EPA system ID: WI2681104. Ask the utility on your bill for your address in their service line inventory.
Knollcrest's lead record
That is up 6.21 ppb from 7.43 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Knollcrest is 13.64 ppb across 3 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 13.64 ppb over 10 |
| 2020 | 7.43 ppb |
| 2017 | 3.65 ppb |
How Knollcrest 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. Knollcrest's 13.64 ppb sits at the 99th percentile in Wisconsin and the 98th nationally (higher means more lead).
Other water systems in Waukesha County
71 other systems share Waukesha County; 0 of them have a higher latest lead result than Knollcrest. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Waukesha Water Utility | 70,718 | 0.56 ppb |
| Brookfield Water Utility | 29,070 | 1.5 ppb |
| New Berlin Water Utility | 27,899 | 0.33 ppb |
| Menomonee Falls Ww - Surface Water | 23,867 | 2.1 ppb |
| Oconomowoc Waterworks | 15,805 | 6.8 ppb |
| Sussex Village Hall & Water Utility | 11,750 | 1.8 ppb |
| Hartland Waterworks | 9,212 | 4.2 ppb |
| Pewaukee City Water And Sewer Utility | 8,671 | 2.6 ppb |
| Mukwonago Waterworks | 8,190 | 3.2 ppb |
| Pewaukee Village Waterworks | 8,166 | 1 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Middleton, 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 Knollcrest 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. See what changes at 10 ppb in 2027.