Koshkonong Pws, MO
Exceeded the action level in the past
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2024-2026). 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.
Who runs the water here
Koshkonong Pws serves about 212 people through 104 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 Oregon County, Missouri. EPA system ID: MO4010434; phone on file: 417-293-2830. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
Against the period ending 2023 (0.58 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Koshkonong Pws is 56.93 ppb across 10 monitoring periods, 2 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2023 | 0.58 ppb |
| 2023 | 0.58 ppb |
| 2020 | 0 (not detected) |
| 2019 | 2.02 ppb |
| 2019 | 56.93 ppb over 15 |
| 2018 | 8.31 ppb |
| 2018 | 7.48 ppb |
| 2017 | 56.93 ppb over 15 |
| 2016 | 1.79 ppb |
Where this result ranks
Of the 1,674 Missouri systems with a lead result, the median latest reading is 1.04 ppb; 2 are over 15 ppb right now and 74 have gone over at some point. Koshkonong Pws's reported as 0 (not detected) sits at the 15th percentile in Missouri and the 16th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
4 other systems share Oregon County; 1 of them has a higher latest lead result than Koshkonong Pws. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Thayer Pws | 2,200 | 1.02 ppb |
| Alton Pws | 1,000 | 0 (not detected) |
| Oregon County Pwsd 1 | 900 | 0 (not detected) |
| Oregon County Pwsd 2 | 120 | 0 (not detected) |
Next steps for Koshkonong, MO
Test your own tap with a certified lab first-draw sample; Koshkonong, MO 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 Koshkonong Pws 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. Why an old exceedance still matters: over the limit before, under it now.