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Missouri Water Quality
652
Utilities in database
5.5M
Residents served
30%
On private wells
3
Key contaminants tracked
Drinking Water in Missouri
Missouri has 652 community water systems serving approximately 5.5 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, arsenic, nitrates. 30% of Missouri residents rely on private wells. MoDNR holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Missouri
Top 20 of 652 by populationMo American St Louis St Charles Counties
MO6010716 · 1,111,000 served
Kansas City Pws
MO1010415 · 513,800 served
St Louis City Pws
MO6010715 · 304,709 served
Springfield Pws
MO5010754 · 210,898 served
City of Columbia Utilities
MO3010181 · 126,254 served
Independence Pws
MO1010399 · 120,000 served
St Charles County Pwsd 2
MO6024530 · 100,587 served
Lees Summit Pws
MO1010459 · 99,400 served
Mo American St Joseph
MO1010714 · 89,171 served
Mo American Joplin
MO5010413 · 73,728 served
St Charles Pws
MO6010707 · 73,040 served
Blue Springs Pws
MO1010080 · 61,084 served
St Peters Pws
MO6010719 · 52,575 served
Wentzville Pws
MO6010849 · 41,784 served
University of Missouri Columbia
MO3069001 · 40,000 served
Cape Girardeau Pws
MO4010136 · 39,941 served
Jefferson Co Cons Pwsd C 1
MO6024295 · 37,000 served
Fort Leonard Wood
MO3079500 · 34,000 served
Ofallon Pws
MO6010588 · 32,515 served
Liberty Pws
MO1010466 · 30,800 served
Key Contaminant Concerns in Missouri
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always from human activity — nitrate interferes with the blood's ability to carry oxygen. The United States produces over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Arsenic
Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.
Missouri Water FAQs
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Data source: Utility data from EPA SDWIS. 652 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-19