Grafton Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 3.3 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. 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.
Grafton Waterworks at a glance
Grafton Waterworks serves about 12,269 people through 4,544 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Ozaukee County, Wisconsin. EPA system ID: WI2460111. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
Against the period ending 2020 (3.3 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Grafton Waterworks is 3.9 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 3.3 ppb |
| 2020 | 3.3 ppb |
| 2017 | 3.9 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. Grafton Waterworks's 3.3 ppb sits at the 78th percentile in Wisconsin and the 84th nationally (higher means more lead).
Neighbouring systems
46 other systems share Ozaukee County; 6 of them have a higher latest lead result than Grafton Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Port Washington Waterworks | 12,853 | 5.9 ppb |
| Cedarburg L & W Commission | 12,500 | 7.6 ppb |
| Mequon Water Utility | 11,152 | 0.52 ppb |
| Saukville Waterworks | 4,268 | 7.6 ppb |
| Belgium Waterworks | 2,493 | 1.3 ppb |
| Fredonia Waterworks | 2,279 | 0 (not detected) |
| Concordia University | 1,500 | 0.3 ppb |
| Mequon Trail Townhomes | 615 | 0.57 ppb |
| Huntington Park | 600 | 1.02 ppb |
| Beechwood Farms Estates | 300 | 0.27 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Grafton, 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 Grafton Waterworks 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. The action level is dropping - the 10 ppb rule from 2027.