Williamsburg Public Water Supply, IA
Exceeded the action level in the past
Latest 90th-percentile lead: 3 ppb (monitoring period 2024-2024). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest result is under the action level, but this system has gone over 15 ppb before. Lead comes from pipes, not the source water, so a home with a lead service line can still be exposed. Test your own tap.
About Williamsburg Public Water Supply
Williamsburg Public Water Supply serves about 3,345 people through 1,332 service connections, which makes it a medium-sized system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Iowa County, Iowa. EPA system ID: IA4884023; phone on file: 319-330-8638. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Williamsburg Public Water Supply's lead record
Against the period ending 2023 (2 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Williamsburg Public Water Supply is 18.3 ppb across 10 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 3 ppb |
| 2023 | 2 ppb |
| 2022 | 3.7 ppb |
| 2022 | 2.9 ppb |
| 2021 | 2.5 ppb |
| 2020 | 4 ppb |
| 2020 | 6.6 ppb |
| 2019 | 18.3 ppb over 15 |
| 2019 | 5.6 ppb |
| 2018 | 1.8 ppb |
Against other Iowa systems
Of the 1,066 Iowa systems with a lead result, the median latest reading is 1.4 ppb; 4 are over 15 ppb right now and 36 have gone over at some point. Williamsburg Public Water Supply's 3 ppb sits at the 77th percentile in Iowa and the 82nd nationally (higher means more lead).
Neighbouring systems
10 other systems share Iowa County; 2 of them have a higher latest lead result than Williamsburg Public Water Supply. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Poweshiek Water Association (Iac) | 2,490 | 0.9 ppb |
| Marengo Water Supply | 2,435 | 1.2 ppb |
| Amana Society Water System North | 1,248 | 0 (not detected) |
| North English Water Department | 1,065 | 0 (not detected) |
| Victor Municipal Water Dept | 875 | 18.2 ppb |
| South Amana Water Supply | 300 | 2 ppb |
| Ladora Water Supply | 229 | 0 (not detected) |
| Millersburg Water Dept | 135 | 0 (not detected) |
| Waldenburg Community Water System | 90 | 2 ppb |
| Iowa Valley Estates | 46 | 8 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Williamsburg, IA 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 Williamsburg Public Water Supply whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1360 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. Why an old exceedance still matters: over the limit before, under it now.