Cole County, Missouri: drinking water report. Cole County in central Missouri has about 77,000 residents, with Jefferson City – the state capital – as the…
Cole County in central Missouri has about 77,000 residents, with Jefferson City – the state capital – as the county seat. The Missouri River provides the primary water source, with Jefferson City Water Division operating the treatment plant. The Missouri River at Jefferson City carries agricultural and municipal inputs from its upstream watershed, including seasonal pulses of herbicides and nutrients.
The Missouri River's agricultural load defines the raw water quality at Jefferson City. According to the Missouri DNR's 2024 river monitoring data, atrazine peaked at 2.3 ppb during spring at the Jefferson City intake – below the MCL of 3 ppb but consistently present during the planting season. Nitrate averaged 3.8 mg/L during the same period.
The Jefferson City Memorial Airport has documented AFFF use. Missouri DNR's 2024 PFAS investigation found PFOS at 6 ppt in monitoring wells near the facility. The EPA's UCMR5 data showed low-level PFAS in the Jefferson City system consistent with both airport and diffuse urban sources.
Jefferson City's Missouri River water is well-treated, but the agricultural contaminant pulse during spring means raw water quality fluctuates seasonally. Treatment handles the variation, but a household filter adds a consistent baseline.
Check your water for seasonal data. A carbon filter handles atrazine and taste effectively. For PFAS, reverse osmosis adds broader protection. Our water filter guide covers both options. Get your detailed report for seasonal patterns, and visit our Missouri page for statewide context.
Drinking water is one exposure route. These federal datasets also cover Cole County, MO.
The EPA places Cole County, MO in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
49% of homes in Cole County, MO were built before 1980, and 13% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Cole County, MO averages 7.3 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide
9 public water systems serving Cole County, MO have EPA lead testing on record. The reported lead sample skews toward systems that already flagged a problem, so its exceedance rate is not directly comparable with other areas. 1 water systems serving Cole County, MO carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Revised Total Coliform Rule | 1 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.