Boone County Pwsd 4, MO
Lead detected, under the action levels
Latest 90th-percentile lead: 2.49 ppb (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. 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.
Who runs the water here
Boone County Pwsd 4 serves about 6,455 people through 3,117 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 Boone County, Missouri. EPA system ID: MO3024052; phone on file: 573-696-3511. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Boone County Pwsd 4's lead record
That is down 6.78 ppb from 9.27 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Boone County Pwsd 4 is 10.2 ppb across 8 monitoring periods, none of them over 15 ppb (2 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 2.49 ppb |
| 2025 | 9.27 ppb |
| 2023 | 9.27 ppb |
| 2022 | 3.16 ppb |
| 2020 | 3.16 ppb |
| 2019 | 10.2 ppb over 10 |
| 2017 | 10.2 ppb over 10 |
| 2016 | 7.83 ppb |
How Boone County Pwsd 4 compares
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. Boone County Pwsd 4's 2.49 ppb sits at the 77th percentile in Missouri and the 77th nationally (higher means more lead).
Nearby utilities
11 other systems share Boone County; 4 of them have a higher latest lead result than Boone County Pwsd 4. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| City Of Columbia Utilities | 126,254 | 2.1 ppb |
| University Of Missouri Columbia | 40,000 | 2.01 ppb |
| Boone County Cons Pwsd 1 | 24,700 | 3.48 ppb |
| Boone County Pwsd 9 | 15,035 | 3.79 ppb |
| Ashland Pws | 4,999 | 2.84 ppb |
| Boone County Pwsd 10 | 4,963 | 2.41 ppb |
| Centralia Pws | 4,027 | 1.32 ppb |
| Hallsville Pws | 1,732 | 1.81 ppb |
| Sturgeon Pws | 945 | 1.59 ppb |
| Kuhle H20 | 450 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Hallsville, 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 Boone County Pwsd 4 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. Size matters more than most people expect: small vs large water systems.