What was found in ZIP 65203
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Fluoride | 631 µg/L 16% of the EPA limit 4000 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2018
Highest in the ZIP: 1515 µg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 2/3 | SYR4 |
| Copper | 89.62 µg/L 6.9% of the EPA limit 1300 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 863.25 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2018 | 3/3 | SYR4 |
| Barium | 122.5 µg/L 6.1% of the EPA limit 2000 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2018
Highest in the ZIP: 187.7 µg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 2/3 | SYR4 |
| TTHM | 62.43 µg/L 78% of the EPA limit 80 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 70.265 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2019 | 3/3 | SYR4 |
| Lithium | 21.4 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2024
Highest in the ZIP: 68.8 µg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2024 | 2/3 | UCMR-5 |
| Chloroform | 25.81 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 59.3 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 29.86 µg/L 50% of the EPA limit 60 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 54.9 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2019 | 2/3 | SYR4 |
| Nitrate-Nitrite | 37 µg/L 0.4% of the EPA limit 10000 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019 | 2/3 | SYR4 |
| Dichloroacetic Acid | 14.16 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 33.435 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 20.355 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019 | 3/3 | SYR4 |
| Trichloroacetic Acid | 5.885 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 19.76 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2019 | 3/3 | SYR4 |
| Gross Alpha, Excl. Radon And U | 17 pCi/L 113% of the EPA limit, at the 95th percentile of samples — 15 pCi/L Highest in the ZIP: BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 1/3 | SYR4 |
| Lead | 6.945 µg/L 46% of the EPA limit 15 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 15.66 µg/L — THOMAS HILL PWSD 1 · 11,250 people · 2018 | 3/3 | SYR4 |
| Dibromochloromethane | 15.135 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019 | 3/3 | SYR4 |
| Monobromoacetic Acid | 12.6 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019 | 2/3 | SYR4 |
| Chromium | 1.78 µg/L 1.8% of the EPA limit 100 µg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2018
Highest in the ZIP: 6.236 µg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 2/3 | SYR4 |
| Dibromoacetic Acid | 4.552 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019 | 3/3 | SYR4 |
| Combined Radium (-226 And -228) | 3.44 pCi/L 69% of the EPA limit 5 pCi/L Highest in the ZIP: BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 1/3 | SYR4 |
| Bromoform | 3.102 µg/L No EPA limit set Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2019
Highest in the ZIP: 3.366 µg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2019 | 2/3 | SYR4 |
| Combined Uranium | 1.1 µg/L 3.7% of the EPA limit 30 µg/L Highest in the ZIP: BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 1/3 | SYR4 |
| Dichloromethane | 0.6200 µg/L 12% of the EPA limit 5 µg/L Highest in the ZIP: BOONE COUNTY CONS PWSD 1 · 24,700 people · 2018 | 1/3 | SYR4 |
| Pfba | 0.0093 µg/L No EPA limit set Highest in the ZIP: THOMAS HILL PWSD 1 · 11,250 people · 2025 | 1/3 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L Main supplier: CITY OF COLUMBIA UTILITIES · 126,254 people · 2025
Highest in the ZIP: 0.0035 mg/L — BOONE COUNTY CONS PWSD 1 · 24,700 people · 2024 | 3/3 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
Water suppliers serving ZIP 65203
| Supplier | State | Population served |
|---|---|---|
| CITY OF COLUMBIA UTILITIES | MO | 126,254 |
| BOONE COUNTY CONS PWSD 1 | MO | 24,700 |
| THOMAS HILL PWSD 1 | MO | 11,250 |
Frequently asked questions about ZIP 65203 tap water
Is the tap water in ZIP 65203 safe to drink?
EPA testing detected 23 contaminants across the water suppliers serving ZIP 65203. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 65203?
3 public water suppliers report EPA drinking-water monitoring for ZIP 65203. Each is listed above with its population served.
What contaminants are in ZIP 65203's water?
EPA monitoring detected Fluoride, Copper, Barium, TTHM, Lithium, and others across this ZIP's suppliers. The full list with levels and sources is above.