Missouri water quality
Missouri has 3,022 active public water systems (6,170 on file total), 1,688 of them graded by TapGraded.
Grade distribution
Biggest water systems
MO AMERICAN ST LOUIS ST CHARLES COUNTIES
CHESTERFIELD, MO · 1,111,000 served
KANSAS CITY PWS
KANSAS CITY, MO · 553,295 served
ST LOUIS CITY PWS
ST LOUIS, MO · 304,709 served
CITY UTILITIES OF SPRINGFIELD
SPRINGFIELD, MO · 210,898 served
CITY OF COLUMBIA UTILITIES
COLUMBIA, MO · 126,254 served
INDEPENDENCE PWS
INDEPENDENCE, MO · 120,000 served
ST CHARLES COUNTY PWSD 2
O'FALLON, MO · 100,587 served
LEES SUMMIT PWS
LEES SUMMIT, MO · 99,400 served
MO AMERICAN ST JOSEPH
ST JOSEPH, MO · 89,171 served
ST CHARLES PWS
ST CHARLES, MO · 78,961 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
MARYVILLE PWS
MARYVILLE, MO · 10,775 served
CITY UTILITIES OF SPRINGFIELD
SPRINGFIELD, MO · 210,898 served
FARMINGTON PWS
FARMINGTON, MO · 18,217 served
COLE COUNTY PWSD 1
JEFFERSON CITY, MO · 16,548 served
ST PETERS PWS
ST PETERS, MO · 52,575 served
CAPE GIRARDEAU PWS
CAPE GIRARDEAU, MO · 39,941 served
HANNIBAL PWS
HANNIBAL, MO · 17,108 served
KIRKSVILLE PWS
KIRKSVILLE, MO · 17,566 served
WASHINGTON PWS
WASHINGTON, MO · 14,068 served
ST LOUIS CITY PWS
ST LOUIS, MO · 304,709 served
Cities in Missouri
Source: EPA SDWIS/ECHO · Data as of 2026Q2