St Louis County, Missouri: drinking water report. St. Louis County (separate from the City of St.
St. Louis County (separate from the City of St. Louis) serves about 1 million residents in the suburban ring surrounding the city. Missouri American Water is the primary provider, drawing from the Missouri and Meramec Rivers. Some communities operate independent systems. The county's complex jurisdictional structure – over 80 municipalities – means water service is fragmented across multiple providers.
The Missouri River carries agricultural runoff from the Great Plains, while the Meramec River drains a mix of forested, suburban, and former mining landscapes. UCMR5 data shows low-level PFAS detections in county systems. Missouri does not have state-specific PFAS standards.
According to the Missouri Department of Natural Resources' 2024 compliance data, county systems met federal standards. Atrazine – a common agricultural herbicide – is a seasonal contaminant in Missouri River water, though treatment reduces it below MCLs. The legacy of lead mining in the broader region also means some soils carry elevated lead, though this affects soil and dust more than treated drinking water.
With over 80 municipalities, your provider and source water may differ from your neighbor's. Identifying your specific system is step one.
Check your water to see data for your provider. Activated carbon handles taste, atrazine, and some PFAS. Our water filter guide covers options. Pull your detailed report, and visit our Missouri page for statewide data.